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, 45071 Orléans cedex 2, France, tel: (+33/0) 2.38.25.52.60, fax: (+33/0) 2.38.63.12.34, gfacsko@cnrs-orleans.fr

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

CIS HIA-WHISPER Cross Calibration Adrian BLAGAU sent 2 new lists for cross-calibration: HIA HighSens (12 events) 2007-03-21/17:18 - 18:55 SC1 and SC3 2007-04-07/08:00 - 10:05 SC1 and SC3 2007-04-21/15:55 - 17:20 SC1 and SC3 2007-05-03/07:10 - 09:50 SC1 and SC3 2007-06-02/00:00 - 02:10 SC1 and SC3 2007-06-21/07:40 - 09:55 SC1 and SC3 HIA LowSens (10 events) 2007-03-04/03:21 - 05:20 SC1 and SC3 2007-03-11/17:41 - 18:41 SC1 and SC3 2007-04-08/22:20 - 23:59 SC1 and SC3 2007-04-21/07:52 - 09:15 SC1 2007-04-21/07:52 - 08:55 SC3 2007-05-14/11:20 - 12:59 SC1 and SC3 Delivered in January 2010 and available on the Wiki

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)

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

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

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

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

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

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

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

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

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

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

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

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

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

Thank you for your attention!