GENERAL NOTES to produce the user guide:
Contents
1. Name Cross Spectral matrix of the electric field at 27 frequencies from 8 Hz to 4 kHz Property Vector Sizes 27 2 2 2 127frequency bins x 2 Re Im parts x 2x2 matrix Units mV m Hz Significant Digits 3 BE_C _STA_SM depend on time and frequency Name Electromagnetic Cross Spectral ExB products at 27 frequencies from 8 Hz to 4 kHz Property Vector Sizes 27 2 3 2 127frequency bins x 2 Re Im parts x 3x2 matrix Units nTmVmHz1 Significant Digits 3 Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 21 of 43 5 6 STAFF SA AGC Automatic Gain Control Those parameters are mainly given for control purpose as they are derived from an analogue signal Nevertheless it can be useful for plotting large scale data to study the evolution of the wave global power as a function of any parameters The AGC parameters are the average power spectral density in the analogue receivers pass band derived from the AGC signal This is measured in the three large pass band with the same time resolution as PSD A parallel Bz and a perpendicular Bxy component to the spin axis are measured for the magnetic field while only the perpendicular one Exy is measured for the electric field There are three AGC values that are given in nT Hz for the two magnetic AGC Bz Bx and in mV2m 2Hz 1 for one electric AGC Exy There is one value pe2. Name Interval centred frequency tag Sizes 27 Units Hz Significant Digits 4 Frequency BHW C CP STA PSD Name Frequency bin half width Sizes 27 Units Hz Significant Digits 3 Data are separated into two variables one for the magnetic components and another for the electric ones BB_C _STA_PSD depend on time and frequency Name Power Spectrum 8 4000 Hz of the B field components along the ISR2 coordinate axe Property Vector Sizes 27 3 Components Bx2 By2 BZ2 Units nT Hz Significant Digits 3 EE_C _STA_PSD depend on time and frequency Name Power Spectrum 8 4000 Hz of the e field components along the ISR2 coordinate axe Property Vector Sizes 27 2 Components Ex2 E Units mV m1Hz Significant Digits 3 Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 18 of 43 CLUSTER STAFF SA 2003 01 03 07 44 35 187 2003 01 03 08 00 03 140 10 10 CLUSTER 1 lt me Eon SUM OF THE THREE E 107 MAGNETIC POWER 100 E 19 SPECTRAL DENSITIES D ao 104 LEES JL LL eL Lata A Lud ou UR A A a L BALLS 107 10 10 CLUSTER 2 o S 108 SUM OF THE THREE E 107 MAGNETIC POWER 10 j Egs SPECTRAL DENSITIES D do Bari i i iati M Lus RR sd ia 1000 g CLUSTER 3 i Y 10 SUMOFTHE THREE F 197 MAGNETIC POWER 10 E o SPECTRAL DENSITIES a o
3. 2001 crosses 10 r 105r 10 B nT Hz averaged over 10 min 10 707 Lil ropar i 6 3x ial Log d 10 100 1000 f Hz Figure 10 magnetic spectra for different intensities showing that at frequencies below 18 Hz for S C 1 there are instrumental effects in the calibration artificial peak esa Project Cluster Active Archive Doc No Issue Date 154 spectra without whistlers on Cluster 4 107 10 6B nT Hz averaged over 10 min 10 TTTTT T ul L T TTTTTIT T LL 1L ELI 1 T TTTTTIT T T1 lobe moise in 2001 2004 crosses diamonds _ 2008 squares rijal 1 1 10 100 f Hz 1000 CAA EST UG 002 3 0 2011 04 26 Page 32 of 43 Figure 11 Same as s figure 10 for S C 4 Here the user has to be cautious with potential peaks below 35 Hz 6 3 4 Warning considering electric field measurements and related parameters PVSIGN For the use of parameters calculated from the measurement of potentially invalid measurements Some more details are given below For STAFF SA electric field measurements one should not worry about Whisper active modes During active modes of Whisper only the 3 x B coefficients of the matrix are calculated on board thanks to a careful synchronisation by DWP ELECTRIC FIELD the main concern is the partial failure of EFW booms as metionned in 3 where table 3 gives periods of Doc No CAA E
4. 6 3 1 General considerations applicable to all STAFF SA products Concerning the use of the parameters calculated from the measurement of magnetic fluctuations for SM and PSD level 2 products the only warning is the one mentioned above a possible saturation of the waveform at perigee which occurs when perigee is low Ls 2 The Spectral Matrix coefficients are given in a fixed frame of reference on board taking into account the sun pulse for despinning the data This constitutes an issue on the validity of the calculation when the sun pulse is not available This mainly occurs during eclipse periods That is why a caveat file has been produced as explained below NOTSRP files Caveat 1 NOTSRP This dataset contains caveats for the PPP PSD and SM datasets from the STAFF SA instrument This caveats dataset provides the users time intervals when no Sun pulse TSRP was recorded in the S C housekeeping data Note that it can be in eclipse period but not only During those time intervals only the total power density is meaningful In particular no PPP data should be used Caveat 2 PSDNEG As already mentioned when there are PSD negative values they have been replaced by fill values and put in this caveat This dataset contains caveats for the SM datasets from the STAFF SA instrument For a given time and frequency are given the PSD negative values that have been replaced in the PSD data product by a fill value It permits to evaluate th
5. CLUSTER 4 re 10 SUM OF THE THREE E 497 8 E mV m Hz 3 CLUSTER 4 am E SUM OF THE TWO 3 E 10 ELECTRIC POWER 100 t 107 SPECTRAL DENSITIES 10 10 STAFF SA mode Se ae RoR a rR aR Peg Scand puis us qiu a up Cv Weep eae es d 100 0 f CLUSTER 1 ELECTRON i ian CLUSTER 2 GYROFREQUENCY 4 40 Fe o a CLUSTERS 0 1 Le CLUSTER 4 UT 0220 0230 0240 0250 0300 0310 v ow 100 107 anc LETS ana 222 Figure 12 Failure of SC1 probe 1 at 03 02 One can see the sudden saturation of the signal Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 34 of 43 CLUSTER STAFF SA 2009 11 27 08 00 01 001 2009 11 27 15 59 59 916 CLUSTER 1 8 10 SUMOFTHE THREE f d MAGNETIC POWER io SPECTRAL DENSITIES mo Ec ES CSS SSS SPS PSS Sea 10 10 CLUSTER 2 SUM OF THE THREE 7 MAGNETIC POWER SPECTRAL DENSITIES B nT Hz amp CLUSTER 3 N 10 SUM OF THE THREE 7 107 MAGNETIC POWER 10 SPECTRAL DENSITIES m o 107 10 10 CLUSTER 4 uH S 10 SUM OF THE THREE E 107 MAGNETIC POWER 10 SPECTRAL DENSITIES m dps Ma 107 x 10 CLUSTER 1 10 SUM OF THE TWO N E 10 ELECTRIC POWER t 107 SPECTRAL DENSITIES 10 10 10 T 10 CLUSTER 2 10 SUM OF THE TWO F E 10 ELECTRIC POWER t 107 SPECTRAL DENSITIES 10 10 107 T 10 CLUSTER 3 m 10 SUM OF THE TWO B E 10 ELECTRIC POWER t 107 SPECT
6. 10 o 19 4000 _ 10 CLUSTER 4 _ EB 10 SUM OF THE THREE C 107 MAGNETIC POWER 10 10 SPECTRAL DENSITIES D ao s 1000 g 10 CLUSTER 1 10 SUM OF THE TWO E 10 ELECTRIC POWER 100 If 107 SPECTRAL DENSITIES i 10 10 Lolod TN dd a Se c e 107 4000 g 10 CLUSTER 2 I 10 SUM OF THE TWO z 10 ELECTRIC POWER 100 gt 107 SPECTRAL DENSITIES E 107 10 10 4000 g 10 CLUSTER 3 H Eq SUM OF THE TWO N E 10 ELECTRIC POWER 100 z 107 SPECTRAL DENSITIES 10 10 10 4000 g 10 CLUSTER 4 n 10 SUM OF THE TWO i E 10 ELECTRIC POWER gt 100 I 107 SPECTRAL DENSITIES z 10 10 STAFF SA mode 10001 777 757 707 ETT TT aa CLUSTER H 100 ELECTRON cLUSTER2 GYROFREQUENCY YS ey See vy S 3 01 EL s CLUSTER 4 UT 0746 0743 0750 0752 0754 0756 0758 0800 Figure 5 Example of plots of data derived from PSD in the magnetosheath B and E power density for the 4 spacecraft Experiment mode varies from mode 1 5 components to mode 7 3 x B when Whisper experiment is active This explains the white lines on E data Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 19 of 43 5 5 STAFF SA SM Spectral Matrix The Spectral Matrix values for the magnetic electric cross products are B B B BB B E BE B B B B Bi B E B E B B B4B B2 B E B E E B EQBs Ey Bt E EE Ey B Ey B Ey B E E El The SM diagonal t
7. 2002 08 09 present 2a C4 2001 01 01 present 4 Table 5 EFW Operations and STAFF E component quality 4 good quality 2 no saturation caution to absolute values 2a one probe is set to zero density mode V 0 power underestimated 0 625 of the power in mV mt Hz 2b 2 probes are set to zero power underestimated by a factor of 2 0 5 of the power in mV m Hz1 0 one component saturates do not consider using STAFF SA electric component or E field deduced parameters Poynting Vector component 0 many successive operations XX special tests be cautious Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 36 of 43 6 3 5 Warning considering the use of STAFF SA PPP Polarization and Propagation Parameters Warnings given above in particular in what concerns electric field measurements are applicable One should look at table 5 for data validity Quality 2 seems to be good enough in what concerns the direction of the Poynting vector For the PPP use some more caution has to be taken The validity of the results depends on the amplitude of signal Thus a threshold on the total wave power density Magnetic or electric or both point by point should be used e g BSUM threshold for the example presented on Figure 6 is 1 0 E 07 nT Hz Another issue is the validity of the change of frame of reference When there are either low attitude or low FGM coverage the PPP are not calcul
8. 2021 CET DECOMMUTATION STAFF SC 7 CLU CP 122 2021 CET DECOMMUTATION STAFF SA 8 Santolik O Propagation Analysis of STAFF SA Data with Coherency Tests A User s Guide to PRASSADCO LPCE NTS 073 D Lab Phys Chimie Environ CNRS Orleans France 2003 http os matfyz cz PRASSADCO guide pdf 9 Santolik O M Parrot and F Lefeuvre Singular value decomposition methods for wave propagation analysis Radio Sci 38 1 1010 doi 10 1029 2000RS002523 2003 esa Project Cluster Active Archive Doc No CAA EST UG 002 Issue 3 0 Date 2011 04 26 8 Appendix A Acronyms AGC Automatic Gain Control BSUM Sum of the three magnetic auto power spectra CETP Centre d tudes des Environnements Terrestre et Plan taires CS Calibrated Spectra DWF Decommutated Wave Form DWP Digital Wave Processor EFW Electric Field and Wave experiment ELLSVD Ellipticity of the polarization ESUM Sum of the auto power spectra of the two electric antennae GSE Geocentric Solar Ecliptic ISR2 Inverse of SR2 LPP Laboratoire de Physique des Plasmas MFA Magnetic Field Aligned PHSVD Azymuthal Angle Value of the wave vector POLSVD Degree of Polarization in the polarization plane PPP Polarization and Propagation Parameters PSD Power Spectral Density PVSIGN Direction of the Poynting Vector component parallel to the magnetic field SA Spectrum Analys
9. Tango 4 0 2 12 5Hz Log Power nT2 Julian Day 1103 8 January 2003 Log Power Spectral Density nT Hz 8E m Data from step 5 Calibrated data in SR2 system nT with DC Fe 0 10 F1 0 00 F2 12 50 TA k T E Beal Ac Is b ao NP UA BO why WAS pr GTER NAT s i ED Wa lt yo AZAN Th ae 5 N MA 0 T T T T T M T T T F U T 03 00 04 00 05 00 06 00 CLUSTER ROPLOT STAFF cospectro visuspectro4 ps P Robert V Jun 2001 Production date 31 January 2003 10 39 Figure 3 Example of quicklook plot successive crossings of the bow shock Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 14 of 43 5 3 STAFF SC CS Calibrated Spectra These spectra data are given in nT in the GSE frame of reference The calibrated complex spectra frequency time resolutions are 0 098Hz x 10 24s in NBR and 0 109Hz x 9 10s in HBR At Af 1 As the spectra are complex Inverse Fourier Transform can be performed without loss of information With some appropriate wave analysis dedicated software the polarisation and propagation parameters can be obtained in the M F A Magnetic Field Aligned frame of reference using the FGM data that are available at CAA 5VPS or SPIN An example of plot obtained with CS data is given on figure 4 Note that the STAFF SC magnetic waveform data at low frequency around 0 25 Hz may contain some remnant of the spin signal which can become v
10. Vector Sizes 3 Components Bx By Bz Units TM counts Significant Digits 5 Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 12 of 43 It is intended to deliver calibrated waveform data in physical units nT when the new calibration algorithm is finished and tested This can be implemented on continuous data set presently it is done on a defined and limited number of data points due to the frequency dependant transfer function and the successive use of Direct and Inverse Fourier Transforms In the mean time the user should rather use calibrated spectra 5 2 STAFF SC SPECTRO 3 hours routine plots QUICKLOOKS Routine plots produced at LPP are delivered to CAA Those plots are QUICKLOOKS for browsing purposes Each one contents dynamic spectra of the component parallel to the spin axis for the 4 spacecraft for 3 hours of data Data in NBR and HBR telemetry mode are on different plots They can help selecting a shorter time period to analyse or plot An example is given in Figure 3 Cesa Project Cluster Active Archive CENTRE d ETUDE des ENVIRONNEMENTS TERRESTRE ET PLANETAIRES IRES CLUSTER STAFF SC Bz Doc No CAA EST UG 002 Issue 3 0 Date 2011 04 26 Page 13 of 43 Fs Srasc Sdec 0 249330 85 04 60 91 0 249638 85 14 61 05 0 248271 84 99 61 07 0 249238 84 99 61 01 N 512 dt 20 480s df 0 0488 Hz oN Samba 3 Salsa 2 Rumba 1 Frequency Hz
11. the diagonal term of the Spectral Matrix B2 B B B B B E B E Mi By B Bj BD BE DE BaB BB B BE GE E By EB EB E Edu Eb Eye Eye SERO E Those parameters are given in nT Hz for the magnetic components B 2 Bj and B22 and in mV2m Hz Ex and Ey for the electric ones Dynamic spectra can thus be deduced for any component of the electromagnetic or electrostatic waves in the 8 Hz 4 kHz frequency range The electron gyrofrequency is covered by the STAFF frequency range on the complete orbit or a major part of it i e except close to the perigee Note that the time resolution is better for the PSD than for the complete Spectral Matrix elements see Table 1 varying from 0 125 or 0 25 ms in HBR to 1 s in NBR The data delivered to CAA in ISR2 reference frame can be transformed into any reference frame with no hypothesis for the magnetic field components and with the hypothesis E B 0 for the electric components see 2 3 Figure 5 gives an example of dynamic spectra of E and B field for the 4 Cluster Sometimes mainly when the signal level is very low there are negative PSD values in the raw data Those have been replaced by fill values see 6 Supporting data and data are time series data depending on the variable Time C CP STA PSD esa Project Cluster Active Archive Supporting Data are Frequency__C _CP_STA_PSD Doc No Issue Date CAA EST UG 002 3 0 2011 04 26 Page 17 of 43
12. user guide for explanation that is available at CAA The FGM 5VPS data set is the magnetic field vector at the resolution of 0 2s 5 Vectors Per Second Before performing the change of coordinate system PRASSADCO calculates the mean field direction by averaging the 5PVS data on the time interval relevant to the given SM measurement 1 or 4 s Then the time attributed to the considered PPP measurement is the time corresponding to the middle of the interval Then the user should not worry to find a datation different from SM by half a measurement duration 0 5 or 2 s For SM the datation refers to the start time of the measurement interval Supporting data and data are time series data depending on the variable Time C CP STA PPP Supporting Data are Frequency C CP STA PPP Name Interval centred frequency tag Sizes 27 Units Hz Significant Digits 4 Frequency BHW C CP STA PPP Name Frequency bin half width Sizes 27 Units Hz Significant Digits 3 esa Project Cluster Active Archive CLUSTER STAFF SA 2001 07 25 20 00 00 509 2001 07 25 22 29 56 139 1000 100 10 1000 x a SUM OF THE THREE MAGNETIC AUTO POWER SPECTRA SUM OF THE TWO ELECTRIC AUTO POWER SPECTRA DEGREE OF PLANAR POLARIZATI ON e nagnete spectral matte CLUSTER 1 ELLIPTICITY OF POLARIZATION D of he mragnetic spectral matte CLUSTER 1 DE ANGLE CVD of he magnetic spectral ma
13. 8 Hz or 64 Hz in HBR to 4 kHz The time resolution is telemetry mode dependant 1 or 4 s see Table 1 The SVD method is described in 9 The parameters derived from the three magnetic components are THSVD PHSVD ELLSVD POLSVD and BSUM BSUM is the sum of the three magnetic auto power spectra When BSUM is inferior to 1 0E 9 nT2 Hz the calculation of the other magnetic dependant parameters is meaningless The THETA and PHI variables are respectively the wave vector polar and azimuthal angles in Magnetic Field Aligned MFA coordinate system POLSVD and ELLSVD stand for the degree of polarisation between 0 and 1 and the ellipticity beween 1 and 1 respectivelly The sign of EELSVD indicates whether the waves are right handed positive or left handed negative polarised The parameters derived from the electric components are ESUM and PVSIGN ESUM is the the sum of auto power spectra of the two electric antennae PVSIGN is the direction of the Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 23 of 43 Poynting vector component parallel to the magnetic field It is given only when E component is valid Positive negative values correspond to a parallel anti parallel Z component of the Poynting vector The calculation of PVSIGN is meaningless when BSUM is inferior to 1 0E 9 nT Hz 1 and ESUM to 3 0E 9 mV 2m Hz The change of coordinate system has been done using FGM 5VPS data See FGM
14. AFF SC SPECTRO 3 hours routine plots QUICKLOOKS essere tete rtnnnntntns 12 5 3 STAFF SC CS Calibrated SOBEEUS u esae cec t evt re Ee rase Econ mb rne bo toties arenae rrr ter ib 14 5 4 STAFF SA PSD Power Spectral Density suse t andre cpu MO tate wie eee ieelcs 16 5 5 STAFF SA SM Spectral Matrix austin eei coa E RA Io trn UM repa sue nnii 19 5 6 STAFF SA AGC Automatic Gain Control eese eere rnntntn tata taan tata ta tates sata is 21 5 7 STAFF SA PPP Polarization and Propagation Parameters esee 22 6 Recommendations and CayBalsisuueoapuiu Ene umida a i n A ns ctia ber EE 27 6 1 DAYANA A T EA r E A E A E E E E T 27 6 2 We oqe cdb y ccce a n eee ee aN 27 6 3 Use OF STAFF SA qepersUec e niani E A E 30 6 3 1 General considerations applicable to all STAFF SA products 30 6 3 2 TIMIN SSUES srie aeaaea aaa eee ati cree 30 6 3 3 Warning considering magnetic field measurements sss 31 6 3 4 Warning considering electric field measurements and related parameters PVSIGN cee E a E a alee 32 6 3 5 Warning considering the use of STAFF SA PPP Polarization and Propagation PAT ATAVUS pected ode ganar aa a ean e e mua een ea peu 36 6 4 Choice between different Cluster data sets sssssssssssssssssssesceessesssnsssscesesessensseensseseeasseeseseaesneneaeess 36 T sRBIOFGHEDS nisiodo dn tM I ME A ME 38 8 Appendix A ACrOnymMS 20 dieitur did cct
15. Date Project Cluster Active Archive 10 Appendix C description of the Status word Description Values Min Meanings max Step in cal 0 n 0 science mode Step Mode Attenuatio n dB 1 CAL4 0 2 CAL4 0 3 CAL4 0 4 CAL4 0 5 CAL4 13 6 CAL4 26 7 CAL4 39 8 CAL4 52 9 CAL4 65 a CAL4 78 b CAL4 Gnd c CAL3 0 d CAL3 26 e CAL1 0 f CAL2 0 g CAL1 26 h CAL2 26 i CAL1 52 j CAL2 52 k CAL2 Gnd CAL OFF redundant m CAL2 26 n CAL Off On satellite 0 after calibration till reset or new calibration EFW Y boom pair 0 1 0 density mode off 1 density mode on EFW Z boom pair 0 1 0 density mode off 1 density mode on CAA EST UG 002 3 0 2011 04 26 Page 41 of 43 Doc No CAA EST UG 002 esa Issue 3 0 C Date 2011 04 26 Project Cluster Active Archive Page 42 of 43 STAFF SA mode 0 f Value Mode description 0 NM1 1 NM2e 2 NM2b 3 Illegal 4 Emergency 5 Special 6 NM1 e 7 NM1 b 8 FM1 9 FM3e a FM3b b Illegal C FM2 d Illegal e Illegal f Passive STAFF SC mode 0 1 0 SC bandwidth 10 Hz 1 SC bandwidth 180 Hz On board despin 0 1 0 despin off STAFF SA 1 despin on WHISPER 0 1 0 off transmitter 1 active Calibration 0 1 0 off 1 active EFW sweep 0 2 0 no scanning progress 1 scanning 2 non synchronised block Compression 0 2 0 nominal 1 backup 2 no compression Phase 0 3 0 Phase calculation OK Right Sun
16. Date 2011 04 26 Project Cluster Active Archive Page 1 of 43 Doc No CAA EST UG 002 esa Issue 3 0 User Guide to the STAFF measurements in the Cluster Active Archive CAA Version 3 updated by N Cornilleau Wehrlin and STAFF team Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 2 of 43 Content T EPOGCDUE EDODTS edic edades cR iade ciet aeai a AM meiner ce ree ee Moe eU ds da EAD dU 3 2 Instrument DSS CEN aU OU mc 3 2 1 The Magnetic Waveform Unit csssssssssssssssssssssssssssssssssssssssssessssssssessacscsssesesesacscscscsseseseeseeataracsessssaees 3 2 2 The Speebrili ADnalVSel sid e a c Rt ipa at A RE LE neo heen eee ee velo RE cds 4 2 3 Instrument Coordinate SySEBIT ne iai trt notata aaa rana sa aranea Susan d pus Rena Ecke EA RE RR RR R ER asc auf 4 3 Instrument Operations cacumen etude aana a sa bucHdi dis aaa tute uim 6 4 Measurement Calibration and Processing Procedures eene 7 4 1 Production of Level O products and Timing Issues eseeseeresenen entente tete nnns 8 4 2 Production of Level 1 parc et sus acci ci rei cid ns Ru tac erae n Saca Cua ica lu n D DUE 9 4 3 Production of Level 2 and Level 3 Products essere tenente nnne nnn 10 5 Mey Science Measurement and Datasets 59d Da ddnusit otc Sn Ein eibi ductu ees 10 5 1 Level 1 STAFF SC DWF Decommutated Waveform ee seseseseeee entere rtntnntn ratas 11 5 2 ST
17. FW experiment sensitivity the electric PSD data around this frequency should be retrieved preferentially from the STAFF SA experiment At 70 Hz the threshold is 10 mV m Hz Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 38 of 43 7 References 1 Mirioni L Cornilleau Wehrlin N Maksimovic M Burlaud C Robert P Bouzid V Cluster Active Archive Interface Control Document Version 3 CAA STA ICD 0001 2009 http caa estec esa int caa ug cr icd xml 2 Cornilleau Wehrlin N Chauveau P Louis S Meyer A Nappa J M Perraut S Rezeau L Robert P Roux A and C De Villerdary The cluster spatio temporal analysis of field fluctuations STAFF experiment Space Science Review 79 107 136 1997 3 Cornilleau Wehrlin N Chanteur G Perraut S Rezeau L Robert P Roux A Villedary C de P Canu Maksimovic M Conchy Y de Hubert D Lacombe Lefeuvre F Parrot M Pin on J L D cr au P M E Harvey C C Louarn Ph Santolik O Alleyne H St C Roth M Chust T Le Contel O and STAFF team First results obtained by the Cluster STAFF experiment Ann Geophys 21 437 456 2003 4 WEC Instrument User Manual CL WEC UM 002 2009 http caa estec esa int caa dwp docs xml 5 Calibration Report of the STAFF measurements in the cluster active archive CAA CAA EST CR 001 2009 http caa estec esa int caa ug cr icd xml 6 CLU CP 122
18. Pulse 1 Phase calculation OK Sun Pulse interpolated 2 Phase 500 No Sun Pulse 3 Phase 500 No reference phase in SATT Example A status values of 00070110000 means science mode density mode off for EFW Y and Z SA mode NM1 b SC bandwidth 10 Hz SA despin ON Whisper transmitter ON Cal off EFW not scanning Sc compression nominal Phase calculation OK Right Sun Pulse esa Project Cluster Active Archive Doc No Issue Date 11 Appendix D Description of the Compression Error Data are sample into 16 bits for the first record of each block but for other records only the difference is kept coded in 12bits If the difference between two records is too big we may encounter compression errors Fortunately we know on which bit the error occurs which allows us to maximise it Three compression modes are available see Status word character 10 and may lead to one or another bit to be wrong The maximum error is then known see the following table where Delta is the difference between the current record and the previous one CAA EST UG 002 3 0 2011 04 26 Page 43 of 43 Maximum Maximum Delta Compression Error Error 16 bits TM counts mV No Compression 0 65535 0 0 Normal Compression 0 2015 0 0 2016 65535 1024 150 0 511 0 0 512 1535 1 0 15 Backup compression 1536 3587 2 0 3 3588 7447 4 0 6 7448 65535 1024 150 The normal and
19. RAL DENSITIES E 10 10 107 w 10 CLUSTER 4 10 SUMOFTHETWO TE 40 ELECTRIC POWER t 107 SPECTRAL DENSITIES E 10 10 STAFF SA mode t i f CLUSTER 1 Ww 100 ELECTRON i f CLUSTER 2 GYROFREQUENCY 4 40 Le CLUSTER 3 0 1 A Ali d Mehdi uo CLUSTER 4 UT gpa 1000 1100 1200 1300 1400 1500 1600 Xa Re 3 70 3 39 3 06 2 73 2 40 2 06 1 72 1 37 ae M Fr Ieas anne anann ane 4n 4n sana 700 Figure 13 Recovery of E field measurements by putting the failed SC 1 probe 4 in density mode V 0 SC1 E data change after 10 20 from saturated to behaviour comparable to other S C The following table gives the details of EFW operations following probe failures and data quality Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 35 of 43 S C Failed Failure Density mode Time interval STAFF SAE C1 2001 01 01 2001 12 4 27 Pi 2001 12 28 2001 12 28 2002 01 0 03 02 57 27 2002 01 27 2002 01 27 2007 06 2a 12 2007 06 13 XX 2007 06 14 2009 04 2a 18 P4 2009 04 19 2009 04 19 2009 05 0 07 29 00 10 2009 05 10 2009 10 2a 14 P4 2009 10 14 2009 10 14 009 11 0 07 00 00 28 C2 2001 01 01 2007 05 4 13 P1 2007 05 13 2007 05 13 2007 06 0 23 2007 06 23 2007 06 23 present 2a C3 2001 01 01 2002 07 4 28 P1 2002 07 29 2002 07 29 2002 08 0 09 06 59 09 2002 08 09
20. ST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 33 of 43 STAFF SA electric components may be affected by the EFW probe failures on some of the spacecraft see table 3 The STAFF SA onboard despin doesn t permit to get rid of this problem and thus the 2 despun components telemetry data are affected After the failure the electric antenna may be saturated but once EFW has commanded the failed probe into density mode i e set the potential to V 0 the quality is good again but the sensitivity is decreased For one proble failure the underestimation of the electric power is about one third of the total power whereas for 2 probes failures the power is underestimated by a factor of 2 CLUSTER STAFF SA 2001 12 28 02 11 15 517 2001 12 28 03 16 40 589 CLUSTER 1 1003 SUM OF THE THREE f Hz MAGNETIC POWER 100 SPECTRAL DENSITIES B nT Hz 3 10 10 CLUSTER 2 1009 F 10 SUMOFTHE THREE 107 MAGNETIC POWER 10 E aoe SPECTRAL DENSITIES m CLUSTER 3 1000 10 SUMOFTHE THREE MAGNETIC POWER SPECTRAL DENSITIES 8 B nT Hz a f Hz MAGNETIC POWER SPECTRAL DENSITIES B n THz a CLUSTER 1 1000 3I SUM OF THE TWO ELECTRIC POWER SPECTRAL DENSITIES t Hz 8 E mV m Hz a CLUSTER 2 1000 SUM OF THE TWO ELECTRIC POWER SPECTRAL DENSITIES t Hz 8 E mV m Hz a CLUSTER 3 SUM OF THE TWO ELECTRIC POWER SPECTRAL DENSITIES t Hz 10
21. TAFF MK VBa Vot Tw On 30 18120 maas Figure 8 House Keeping data for the same time interval as on Figure 7 The parameter Bmax Bmin amplitude of the analog waveform is above 10 V Note that the STAFF Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 29 of 43 SA AGC is saturated too Search coil data are invalid between 21 20 and 22 40 UT Figure 7 and 8 show the effect of waveform saturation at perigee The quality of the data at the moment can be verified on the LPP web site looking at the Hiouse keeping plots at http cluster lpp polytechnique fr accueil framepa html A flag will be inserted in the CS data in the future This will permit to eliminate such data from plots as shown on Figure 9 CLUSTER STAFF SC Rumba 1 17 October 2008 Jul Day 3212 Log Power Spectral density nT Hz ZY m Data from step 5 Calibrated data in SAZ systam nT with OC 0 00 12 50 Hz Ne 512 die 204805 di O 04BBHz Foe O10 Fim O00 F2 12 50 By S Pon o o eo 25 Hz ore o On A O CO O50 125 Hz Log Powar nTy2 050 1 23 24 CLUSTER ROPLOT baspectrovisuspectro ps Raprcc Wave V 32 Production date Mon May 10 20 04 38 2010 Figure 9 Same plot than on figure 7 using a flag indicating the waveform saturates on a given component Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 30 of 43 6 3 Use of STAFF SA products
22. al difference of also 10 is seen on S C1 for frequencies lt 8 Hz These differences have now been understood and the calibration functions will be corrected accordingly in the near future see 4 and calibration document 5 LABORATOIRE DE PHYSIQUE DES PLASMAS CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CLUSTER STAFF SC Rumba 1 2008 October 17 Julian day 3212 S dec S rec S freq e612 75902597 Log Power Spectral density nT Hz DAMME Data from Step 5 Data in SR2 system nT with DC 0 125003 Hz 5 4 3 24 D N 512 di 20 4795s dl 0 0498Hz Fo 0 1 F1 0 F2 12 4515 Bx Frequency Hz By Bz 12 4515 Hz D DTP E s L LL Poe ame dte Mae ect OE i Qm i U T 21 00 22 00 23 00 24 00 Bperp DC nT Log Power nTF D in RCL VISUSPECTRO V20090629 Production date May 10 15 50 2010 Figure 7 Plot of CS data during a waveform saturation period DC field 2000nT CLUSTER WEC HK SAT 1 Rumba 2008 10 17 OBDH Acquisition Mode 22 00 DWP Status 23 00 24 00 Staff SC 10 ae su e710 F 1721 n a 21 22 00 23 00 24 E Backup lt AGC B 8 m ByzA PER um i e P EN pad 4 15l p 100 oer aa astitit doa ive Byc Staff SA i Id o LIU NM i M LU BMG MH IK i MM M MA 21 00 22 00 23 00 24 00 risp Sa Actif espin On EZ Density Miscellaneous Status sc SA CLUSTERIS
23. ated the change in MFA frame of reference being not possible PPP data are replaced by fill values The description of these fill values will be included in a future caveat called UNDEFINED MFA 6 4 Choice between different Cluster data sets Results of cross calibration studies see 5 give the following indication for the choice of a given experiment when performing similar measurements Magnetic fluctuations Frequency 0 1 0 5 Hz 0 5 1Hz 1 10Hz 1 10Hz gt 10 Hz ange B lt 10 4 nT Hz1 B gt 10 4 nT Hz Instrument FGM X X X STAFF SC X X X X STAFF SC X STAFF at frequencies around spin doesn t despin the data as well as FGM Above 1 Hz the sensitivity of STAFF instrument is better than FGM one WBD and STAFF Those experiments are complementary in the frequency range 25 Hz to 4 kHz when WBD operates in its default mode 25Hz 9 5 KHz frequency coverage WBD has a good frequency time resolution with only one component E or B and doesn t operate the whole time but rather by periods of one hour per orbit STAFF permits polarization studies Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 37 of 43 Conclusion of comparisons between STAFF SA and EFW see ref 5 The agreement is good while the electric fluctuations level around 8 8 Hz is larger than 6 to 10 x 10 4 mV m Hz As this latter value is known to be close to the E
24. backup compression are used respectively when we expect to measure low and high amplitude signals including large spin signals
25. e validity of the SM power density value including those negative PSD in its calculation see 5 4 and 5 5 6 3 2 Timing issues As mentioned in 5 3 one shouldn t worry about a difference of timing between STAFF SA SM and PPP For a given time interval 1 s or 4 s depending on bit rate mode SM are dated at the beginning of the interval whereas PPP are date at the middle of the time interval PPP are time stamped either 0 5 s or 2 later Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 31 of 43 6 3 3 Warning considering magnetic field measurements There may be some 10 96 differences between SC1 calibration and other three spacecraft see 4 and ref 5 Continuity between STAFF SC and STAFF SA is insured 5 Nevertheless there are some artefact in the STAFF SA calibration about which the user should be advised in order to not miss interpret the data Figures 10 and 11 show superimposition of magnetic spectra for different signal intensities for SC 1 and SC 4 respectively One can see that some fluctuations of the noise level of the experiment do propagate whatever the intensity of the signal The affected frequencies are below 18 Hz for S C 1 and below 35 Hz for S C 4 S C 2 and 3 are under study Interferences are hidden for strong enough signal see e g interference at 70 Hz 149 spectra without whistlers om Cluster 1 10 3 TrTI T T VETEITE T T BELL T T T lobe noise in
26. encadi uta actui cott atunt 39 9 Appendix B The STAFF datasets stored in the CAA esee eseeeeeten entente ntnnnn tnnt tnter 40 10 Appendix C description of the Status word sese eene entente entente tnter internos 41 11 Appendix D Description of the Compression Error eese eene nennen tnter ntes 43 Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 3 of 43 1 Introduction This document provides a brief outline of the data archiving from the STAFF experiment on Cluster in the ESA Cluster Active Archive CAA First the CLUSTER STAFF experiment is briefly described including its operations and failures as well as the calibration and processing procedures of the measurements Afterwards the key Science measurements and datasets are described including some general warnings and recommendations for the users of the STAFF datasets All STAFF datasets available on the CAA are listed in appendix A NOTE the present document describes the data as of 22 April 2011 Since the CAA is an active archive new datasets are added and existing datasets are updated continuously and the User Guide will be updated accordingly 2 Instrument Description The CLUSTER STAFF instrument comprises a tri axial search coils magnetic sensors 0 1Hz 4 kHz frequency range and two on board wave analysers a magnetic waveform unit STAFF SC and a wave spectrum a
27. er SC STAFF Wave form data from Search Coils only SM Spectral Matrix SR2 Spin Reference 2 SSW6RF STAFF Sensor WEC6 Reference Frame TCOR Time CORorrection TED Software to extract instrument data from WEC science data packages and to time the data using HK data THSVD Polar Angle Value of the wave vector Page 39 of 43 esa Project Cluster Active Archive Doc No CAA EST UG 002 Issue 3 0 Date 2011 04 26 Page 40 of 43 9 Appendix B The STAFF datasets stored in the CAA Dataset name Dataset title Visibility in the CAA C _CP_STA_AGC Automatic Gain Control Both Web Command line C _CP_STA_PSD Power Spectral Density 8 Hz 4 kHz Both Web Command line C CP STA SM Spectral Matrix 8 Hz 4 kHz Both Web Command line C CP STA PPP Polarization and Propagation Parameters 8 Hz 4 kHz Both Web Command line C CP STA DWF NBR HBR Magnetic Field Waveform uncalibrated 25 or 450 Hz sampling Both Web Command line C CP STA CS NBR HBR Magnetic Field Spectra in GSE up to 12 5 Hz NBR 225 Hz HBR Both Web Command line CL CG STA SC SPECTRO NBR Plot Bz Spectral Density for all spacecraft burst up to 225 Hz Both Web Command line 1 This is the title visible in the CAA web GUI for downloading Doc No esa Issue C
28. erms contain three magnetic components B given in nT Hz and two electric components Ei given in mV2m Hz like PSD The cross products Bi x Ej are expressed in nT mV mHz From this data set once in the MFA wave characteristics polarisation ellipticity direction for propagation etc can be retrieved Those parameters are now starting to be delivered at CAA see 5 7 Note that the diagonal terms values of the matrix are the result of an average over 4 or 8 successive PSD values Supporting data and data are time series data depending on the variable Time C CP STA SM Supporting Data are Frequency C CP STA SM Name Interval centred frequency tag Sizes 27 Units Hz Significant Digits 4 Frequency BHW C CP STA SM Name Frequency bin half width Sizes 27 Units Hz Significant Digits 3 Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 20 of 43 Data are separated into three variables one for the magnetic components BB one for the electric components EE and one for the BE cross products BB C STA SM depend on time and frequency Name Cross Spectral matrix of the magnetic field at 27 frequencies from 8 Hz to 4 kHz Property Vector Sizes 27 2 3 3 127frequency bins x 2 Re Im parts x 3x3 matrix Units nT Hz Significant Digits 3 EE_C _STA_SM depend on time and frequency
29. ery strong around perigee in strong magnetic fields see 6 Supporting data and data are time series data depending on the variables Time C CP STA CS NBR HBR Supporting Data are Frequency C CP STA CS NBR HBR Name Frequency bins Sizes 128 Units Hz Significant Digits 4 Data Complex Spectrum C STA CS NBR HBR depend on time and frequency Name Components of the Magnetic Field Complex Spectrum Property Vector Sizes 128 2 3 Components Re Im Units nT Significant Digits 4 Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 15 of 43 LABORATOIRE DE PHYSIQUE DES PLASMAS CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CLUSTER STAFF SC Samba 3 2003 January 08 Julian day 1103 S dec S rasc S freq 107 8499 02487 Log Power Spectral density nT 2 Hz Data frorn Step 5 Data in SR2 system nT with DC 0 12 5001 Hz N 512 dt 20 4799s df 0 0488Hz Fc 0 1 F1 0 F2 12 4513 12 4513 Hz 1 oo E o g a 5 U T RCL VISUSPECTRO V20090629 Production date May 12 16 19 2010 Figure 4 Example of plot for 3 components obtained from CS data Zoom of Figure 3 Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 16 of 43 5 4 STAFF SA PSD Power Spectral Density The Power Spectral Densities values for the magnetic and the electric field are
30. eys Bx SpaceCraft Body Build System Figure 1 STAFF antenna reference frame For STAFF SC level 2 data CS products coming from the wave form data are given in GSE For STAFF SA data the level 2 products are given in ISR2 inverse of SR2 Spin Reference 2 close to GSE Geocentric Solar Ecliptic ISR2 has been chosen instead of GSE usually used as there are only 2 electric components any transformation to a coordinate system which is not in the satellite spin plane needs to do the hypothesis E B 0 We decided not to apply this assumption as the STAFF SA level 2 data are the most complete data set of this part of the experiment to be kept in CAA In the case of STAFF SA L3 delivery products Polarization and Propagation Parameters the coordinate system is the meaningful one for such data the MFA Magnetic Field Aligned There is no risk to loose information as it is always possible to recalculate these parameters starting from level 2 data Spectral Matrix For the definition of GSE SR2 MFA see eg the CAA metadata dictionary 7 7 http caa estec esa int documents DataDic pdf Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 6 of 43 3 Instrument Operations Different operational modes have been applied mainly depending on the bit rate either normal NBR or high HBR The complete description of the different possible modes is given in 2 and 4 The ma
31. in characteristics of the most common modes for the waveform and the spectrum analyser are given below in Table 1 and Table 2 The magnetic STAFF SC and electric EFW waveform frequencies are low pass filtered in the same way and are sampled simultaneously as commanded by DWP experiment Other modes are nearly never run at the exception of the commissioning phase or special tests Other exception a calibration mode is run once per orbit STAFF SC STAFF SA wave form Spectrum Analyser Bit Rate Frequency Frequency Data Resolution Modes Name Range Range Normal PSD 1s Bit Rate 0 1 10 Hz 8 Hz 4 kHz NM1 NM1 b SM 4s High PSD 0 125 or 0 25s Bit Rate 0 1 180 Hz 64 Hz 4kHz FM1 or FM2 FM3b SM 1s Table 1 STAFF modes main characteristics as a function of Telemetry mode PSD Power Spectral Density and SM Spectral Matrix The content of STAFF SA data depends both on the bit rate frequency range and time resolution cf Table 1 and the Whisper mode cf Table 2 The Whisper active sounding lasts for a few seconds about 3 seconds usually every 52 or 104 seconds DWP synchronises perfectly STAFF SA and Whisper operational modes so that the sounding effect whisper sounder on is always within one sample only for 4s resolution STAFF SA spectral matrix There is no calculation of the spectral elements comprising electric field data during those 4 seconds There are no electric field data when whisper is active
32. ine CLUSTER 1 AZIMUTHAL ANGLE PHI E magnetic spectra mate CLUSTER 1 NORMALIZED Z COMPONENT OF THE POYNTING VECTOR FROM Ant Ant iHz iHz iHz Hz tHe r Hz UT R IR MLat dog MLT fi 5 En Doc No Issue Date ha ELT moa lunar tti zo 76 4n n3 mn se P amp 14 84 14 86 14 86 a el dr aici Ai NN 3e 2120 p aT T 14 83 14 78 Er 14 60 14 60 CAA EST UG 002 ESUM CLUSTER 1 BSUM CLUSTER 1 PCOLSVD CLUSTER 1 Fhi dag 3 0 2011 04 26 Page 24 of 43 BSUM ESUM HB POLSVD ELLSVD P THSVD PHSVD PVSIGN 2 Figure 6 Example of Polarization and Propagation Parameters PPP plot Below a certain power density value PPP are not plotted to help interpretation here the threshold is 1 0 E 07 nT Hz 1 esa Project Cluster Active Archive Doc No CAA EST UG 002 Issue 3 0 Date 2011 04 26 Page 25 of 43 Data are separated into seven variables The parameters calculated from the three magnetic components are THSVD_mfa_C _STA_PPP Name Polar angle of the direction of propagation in MFA coordinate system SVD Property Component Sizes 27 Components THSVD Units Degree Significant Digits 1 PHSVD_mfa_C _STA_PPP Name Azymuthal angle of the direction of propagation in MFA coordinate system SVD Property Comp
33. lation matrix of 5 wave components Bx By Bz Ey Ez over a frequency range superior to 9 octaves at a high rate The 8Hz 4k Hz frequency band is divided into 3 logarithmically distributed frequency sub bands A 8 64Hz B 64 512Hz and C 512 4096Hz each one being divided into 9 frequency channels The analysis band is therefore divided into 27 frequency bands logarithmically spaced 2 3 Instrument Coordinate System STAFF level 2 and level 3 data products are given in despun coordinate systems as detailed below Nevertheless STAFF SC level 1 wave form DWF data are given in the instrument reference frame in order to keep all available information For instance the onboard compression of the waveform data is performed on each individual component i e in the instrument reference frame this allows evaluating the compression quality This reference frame is called SSW6RF STAFF Sensor WEC6 Reference Frame and has been chosen to be the same as EFW instrument coordinate system in the spin plane at 45 of the satellite body built reference frame the third component orthogonal to the 2 others is parallel to the spacecraft X axis parallel to the spin axis at the first order of precision This is shown on the figure which follows Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 5 of 43 Spin P STAFF sensors with deployed boom Sun Bz Ez By Ey sensor SCx s
34. nalyser STAFF SA The latter calculates the complete spectral matrix for the 3xB magnetic field 2xE electric field wave components The wave electric fields measured by the four spherical EFW sensors are transmitted to and analysed by the STAFF SA electronics For more details about instrument description see documents 1 2 3 and 4 2 1 The Magnetic Waveform Unit The magnetic waveform unit STAFF SC is made of various sections to fulfil different filtering and waveform digitalisation output interface and on board calibration for the whole STAFF experiment Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 4 of 43 The three magnetic components of the magnetic field Bx By and B at the output of the search coil preamplifiers are simultaneously filtered in either 0 1 10Hz or 0 1 180Hz bandwidths depending on the spacecraft telemetry mode NBR Normal Bit Rate and HBR High Bit Rate respectively Then the three components are simultaneously digitised by 16 bits sampling at 25 or 450 Hz according to the previous telemetry modes STAFF and EFW waveforms are sampled simultaneously and synchronized by the Digital Wave Processor DWP Note that EFW and STAFF filters have been identically designed for further combined electromagnetic waveform data analysis 2 2 The Spectrum Analyser The Spectrum Analyser STAFF SA is designed to perform the complete auto and cross corre
35. ndard STAFF science data status the spin phase is computed from the Sun Reference Pulse SRP and added in the L1 file in order to permit further transformation of the data in any reference frame The quality of the phase determination depending on the presence or not of the SRP information in the auxiliary data is given in the status word The Status is a word of 11 ASCII characters each depending on one different factor The status word is composed as follows Step in cal EFW Y EFW Z Mode SA Mode SC Despin SA WHISPER Calibration EFW sweep Compressio Phase Table 4 STAFF status word The value of each character is explained in appendix C Doc No CAA EST UG 002 esa Issue 3 0 Date Project Cluster Active Archive 2011 04 26 Page 10 of 43 4 3 Production of Level 2 and Level 3 Products Figure 2 b below shows the processing chain for getting level 2 and level 3 products from the level 1 described above Details on the different products are given in the next section E 4 L2 Files f 13 Files we Vd Figure 2 b processing chain to obtain Level 2 and 3 from Level 1 5 Key Science Measurement and Datasets Level 1 STAFF SC products are delivered in the STAFF Sensor WEC6 Reference Frame SSW6RF Level 2 STAFF SC products are delivered in GSE coordinate system Level 2 STAFF SA products are delivered in ISR2 system where T stands for inver
36. of telemetry mode and should help choosing a STAFF data set MM ANDEREN NBR 8 64 180 I 1 H L4 Y q i 0 1 1 10 100 1000 4000 Frequency Hz o rugs NR SR HBR SC Waveform 3xB SA Spectral Matrix 3x B 2xE 6 1 DWF As the DWF files from STAFF SC are not calibrated data they can t be used straightforward by the scientists These data are time tagged using TCOR option In the absence of the forthcoming calibrated waveform product CWF the most interesting STAFF SC data are the calibrated spectra 6 2 Use of CS Data Those data are calibrated and can be used with no restriction the calibration being stable over time The calibrated spectral measurements are good considering the quality except for the spin frequency where strong noise is observed especially on the X and Y components at perigees esa Project Cluster Active Archive Doc No CAA EST UG 002 Issue 3 0 Date 2011 04 26 Page 28 of 43 There may be a remnant of the spin signal close to perigee Moreover the perigee has decreased with time Since 2008 there is a saturation of the waveform around perigee There is no warning for the saturation at the moment This will be added later on The effect of the spin signal and of saturated data can be seen on the plots below A systematic underestimate of the amplitude of the magnetic fluctuations with respect to FGM has been evidenced of the order of 10 An addition
37. onent Sizes 27 Components PHSVD Units Degree Significant Digits 1 ELLSVD_C _STA_PPP Name Ellipticity of the polarization SVD Property Component Sizes 27 Components ELLSVD Units Unitless Significant Digits 2 POLSVD_C _STA_PPP Name Degre of polarization in the polarization plane SVD Property Component Sizes 27 Components POLSVD Units Unitless Significant Digits 2 Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 26 of 43 BSUM C STA PPP Name Sum of the three magnetic auto power spectra Sizes 27 Components POLSVD Units nT Hz 1 Significant Digits 2 The parameter calculated from the three magnetic components and the two electric components is PVSIGN_C _STA_PPP Name Parallel component of the Poynting vector normalized by its standard deveiation Property Magnitude Sizes 27 Components PVSIGN Units Unitless Significant Digits 2 The parameter calculated from the two electric components is ESUM_C _STA_PPP Name Sum of the two electric auto power spectra Sizes 27 Components ESUM Units mV2 m Hz1 Significant Digits 2 Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 27 of 43 6 Recommendations and caveats The scheme below shows the data availability as a function
38. r frequency band of the analyser A 8 64Hz B 64 512Hz and C 512 4096Hz Supporting data and data are time series data depending on the variable Time C CP STA AGC Supporting Data describe the three frequency bands A B C Each band is defined with the interval centred frequency and the frequency bin half width Frequency C CP STA AGC Name Interval centred frequency tag Sizes 3 Units Hz Significant Digits 4 Frequency BHW C CP STA AGC Name Frequency bin half width Sizes 3 Units Hz Significant Digits 3 Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 22 of 43 Data are separated into two variables one for the magnetic AGC one for the electric AGC B C STA AGC depend on time and frequency Name Magnetic AGC Property Vector Sizes 3 2 Components Bz Bxy Units nT Hz1 Significant Digits 3 E_C _STA_AGC_ depend on time and frequency Name Electric AGC Property Vector Sizes 3 Components Exy Units mV mHz Significant Digits 3 5 7 The PPP give polarisation and propagation parameters for electromagnetic waves They are STAFF SA PPP Polarization and Propagation Parameters derived from singular value decomposition SVD of the cross spectral matrix SM using the PRASSADCO program 8 at 27 or 18 in HBR logarithmically distributed frequencies between
39. r inter spacecraft comparisons Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 9 of 43 The comments which follow only concern a future utilisation of STAFF waveform data In the case of simultaneous utilisation of EFW waveform the user should verify that the same option has been chosen for those concerned data set production by EFW team As there are some gaps in TCOR files all data are not time corrected For the moment there are no flag in the data to inform the users when data are not corrected Presently this concerns only the uncalibrated waveform data as calibrated spectra have a 10 s time resolution In the next future a status on time correction availability will be given in a new version of DWF and in the the calibrated waveform data files For the moment the users can check the TCOR CAVEAT files provided by DWP For STAFF SA TED version 2 4 3 is used an accuracy of sub millisecond is not needed as the best STAFF SA time resolution in HBR is only 125 ms This version insures an accuracy of 4 ms 4 2 Production of Level 1 products The decommutation to go from LO to Level 1 L1 is done by software written in LPP previously CETP Data are decompressed See documents 6 and 7 for details Depending on the data set some status informations are given Only STAFF SC level one data are delivered to CAA namely DWF see 5 1 For STAFF SC data in addition to the sta
40. t has not varied with time at the date of April 1st 2011 e A difference of 10 in the transfer function of S C 1 with respect to other spacecraft underestimates the amplitude of the magnetic field fluctuation below 8 Hz on this spacecraft e A general under estimation of about 8 of the magnetic field fluctuations with respect to FGM has been noticed e Those differences are now understood and should be corrected soon and before delivery of Calibrated Wave Form CWF data product Doc No CAA EST UG 002 esa se Date Project Cluster Active Archive Figures 2 a and 2 b summarize the processing procedures e CA ead Normal N 1i Z les a5 C Uu un e TSS NO Bd Qe NN purre SSS QII 72 o f SATT f i 7 Lie A A y f 4 QZZZZZZZZZZZZ Figure 2 a processing chain to obtain Level 0 and Level 1 4 1 Production of Level 0 products and Timing Issues TED software produced by the DWP team is applied to WEC data provided by ESOC in order to get Level 0 LO files At this stage STAFF science data are separated into two different data sets STAFF SC and STAFF SA and time tagged thanks to the WEC Housekeeping data and TED The TED version 2 5 is run to extract STAFF SC data files to get the best possible time accuracy by activating the option using TCOR files in order to reach a time accuracy of the order of some microseconds which is important mainly for wave data in high bit rate fo
41. ted spin axis Level 3 STAFF 2 3 SA products are delivered in Magnetic Field Aligned MFA coordinate system see paragraph Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 11 of 43 5 1 Level 1 STAFF SC DWF Decommutated Waveform The DWF data are given in telemetry counts in the SSW6RF frame and are stored in the archive as reference data for the case of any reprocessing in particular in case of data re calibration This dataset contains the maximum of information for any further data processing status phase compression error level if any the best time accuracy A new version 4 will incorporate the time of start of the telemetry data packets time at which TCOR is applied Supporting data and data are time series data depending on the variables Time C CP STA DWF NBR HBR Supporting Data are Status C CP STA DWF NBR HBR described in table 4 and appendix C Name STAFF SC status Significant Digits 11 Phase Angle SC C CP STA DWF NBR HBR Name Phase Angle Units Degree Significant Digits 5 MaxCompkError xyz Instrument C CP STA DWF NBR HBR described in appendix D Name Maximum compression Error Property Vector Sizes 3 Units TM counts Significant Digits 4 Data B vec xyz Instrument C STA DWF NBR HBR Name Cluster NBR HBR Magnetic Field Decommutated Waveform Property
42. this is why one can see white lines or data gaps on electric dynamic spectra see e g figure 5 Doc No CAA EST UG 002 esa Issue 3 0 Date 2011 04 26 Project Cluster Active Archive Page 7 of 43 WHISPER MODE STAFF SA components STAFF SA Mode Names active 3xB NM1 FM1 FM3 passive 3xB 2xE NM1 b FM3b Table 2 Main STAFF SA modes as a function of Whisper experiment mode active or passive STAFF SA electric components may be affected by the EFW preamplifier failure on some of the spacecraft see table 3 The STAFF SA onboard despin doesn t permit to get rid of this problem and thus the 2 despun components telemetry data are affected After the failure the electric antenna may be saturated but once EFW has commanded the failed probe into density mode i e set the potential to V 0 the quality is good again but the sensitivity is decreased This is detailed in 6 3 Spacecraft number Probe number Dateoffailure Density mode implementation 2001 12 28 2002 01 27 2009 10 14 2009 11 28 2007 05 13 2007 06 23 2002 07 29 2002 08 09 o N an Rl aR Table 3 Dates of failure of EFW components and date of partial recovery density mode implementation 4 Measurement Calibration and Processing Procedures For details on the calibration techniques and results see document 5 To summarise in what concerns magnetic field fluctuations e The state of the instrumen
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