1. WHISPER Cross-caibration activities
Gábor Facskó, Jean-Gabriel Trotignon, Séna Kougblénou, Xavier Vallières, Guillaume Lointier
LPC2E/CNRS, Orléans, France
11th CAA Cross-Calibration Meeting
Goslar, Deutschland
7-9 April 2010
3A, Avenue de la Recherche Scientifique, Orléans cedex 2, France, tel: (+33/0) ,
fax: (+33/0) ,

2. Contents CIS HIA-WHISPER cross calibration
Density determination in the plasmasheet
Applying low-cut off method for the plasmasheet
PEACE-WHISPER cross calibration
Density determination in cusp
Conclusion

3. CIS HIA-WHISPER Cross Calibration
Adrian BLAGAU sent 2 new lists for cross-calibration:
HIA HighSens (12 events)
/17: :55 SC1 and SC3
/08: :05 SC1 and SC3
/15: :20 SC1 and SC3
/07: :50 SC1 and SC3
/00: :10 SC1 and SC3
/07: :55 SC1 and SC3
HIA LowSens (10 events)
/03: :20 SC1 and SC3
/17: :41 SC1 and SC3
/22: :59 SC1 and SC3
/07: :15 SC1
/07: :55 SC3
/11: :59 SC1 and SC3
Delivered in January 2010 and available on the Wiki

4. CIS HIA-WHISPER Cross Calibration (cont’d)
Resonances selected manually (white dots)
Cut-off determined by fptool software (white dots)
Both validated before delivery to CAA
Comparison between active and natural results (statistical comparison will be done soon)

5. Cut-off determination in the plasmasheet
WHISPER
Fqs were originally thought to be used to determine the density inside the plasmasheet
Using WHISPER active mode
Fpe, Fuh, Fqn  Ne
A lower z-mode cut-off was identified in WBD data (O. Santolik et al.) from which the density can be determined.
WBD

6. Cut-off determination in the plasmasheet (cont’d)8 6 4 2
kHz
WBD
WHISPER
This lower cut-off is also visible in the natural measurements of WHISPER at low frequency
The density can therefore be determined from this z-mode cut-off frequency using fptool
It is much more efficient to use this natural signature instead of active ones (for resonances are very close to each other, it becomes difficult to distinguish between Fqn and nFce, and polarization effects are strong)
Better temporal resolution with natural

7. Cut-off determination in the plasmasheet (cont’d)8 6 4 2
kHz
WBD
WHISPER
This lower cut-off is also visible in the natural measurements of WHISPER at low frequency
The density can therefore be determined from this z-mode cut-off frequency using fptool
It is much more efficient to use this natural signature instead of active ones (for resonances are very close to each other, it becomes difficult to distinguish between Fqn and nFce, and polarization effects are strong)
Better temporal resolution with natural

8. Cut-off determination in the plasmasheet (cont’d)
The frequency returned by fptool is one of the FFT bins (df=163 Hz)
The frequency determined manually is one of the screen pixels (df ten times less)
Quite good agreement between WBD and WHISPER determinations
No information about the WBD uncertainty

9. Cut-off determination in the plasmasheet (cont’d)
04h10m long period in the plasmasheet
The lower cut-off is clearly visible on natural spectra
Plasma frequency computed from z-mode cut-off frequency superimposed on WHISPER active measurements

10. Cut-off determination in the plasmasheet (cont’d)
The lower cut-off has been determined both manually and using the fptool
Cut-off determined by software with uncertainty are plotted versus manual ones
Straight lines are:
Least square fitting (middle)
fit ± σ (above and bellow)
Cut-off values from software well agree with manual determinations

11. Cut-off determination in the plasmasheet (cont’d)
The colored straight lines are:
Least square fitting (middle)
± n*163 Hz/2, where n=1, 2, 3 (above and bellow)
Points on scattered plot are located close to the perfect y=x line
Quite large regression coefficient (R=0.84)
n=6 Δf≈0.5 kHz

12. Cut-off determination in the plasmasheet (cont’d)
Time intervals where the cut-off has been identified are shown along the four Cluster orbit
Therefore density expected to be determined in the plasmasheet by applying fptool

13. PEACE-WHISPER cross-calibration
No new request from PEACE (CC9-AI-6)
We are doing our best to regularly produce CAA density files
Extended comparison between previous CAA files and calibration dedicated files is ongoing

14. Density determination in the cusp
Cooperation with Frederic PITOUT & Benjamin GRISON
List of cusp events

15. Density determination in the cusp
5Fce
6Fce
Fpe
Green vertical lines show the electron cyclotron frequency harmonics
The vertical purple line gives the plasma frequency
The blue curve is the smooth of the spectral energy. Its maximum is close to the plasma frequency and could be used as a first estimate of the plasma frequency

16. Density determination in the cusp
Time intervals where the cusp signatures have been identified are shown along the four Cluster orbit
Therefore density expected to be determined in the cusp by applying fptool on active measurements

17. WHISPER cross-calibration activities
11th CAA Cross-Calibration Meeting
Goslar, Deutschland
7-9 April 2010
Currently at CAA
+ cusp and plasmasheet
Conclusions
CIS HIA cross-calibration activities to be continued
Plasmasheet and maybe cusp densities could be useful for futur particle measurement calibrations
Density coverage should be soon improved (in cusp and plasmasheet)
using mass production software and/or manual treatment

18. Thank you for your attention!