100 likes | 209 Views
Comparison of STAFF-SA and WBD. Magnetic components of intense whistler-mode chorus. Prepared by Ondrej Santolik. 14th CAA Cross-Calibration meeting , York, 5-7 Oct 2011. Context.
E N D
Comparison of STAFF-SA and WBD Magnetic components of intense whistler-mode chorus Prepared by Ondrej Santolik 14th CAA Cross-Calibration meeting, York, 5-7 Oct 2011
Context • No comparisons between STAFF SA and WBD using magnetic component had ever been presented. An action was pending: • CC8 – AI-45 STAFF :To carry out a cross-calibration study between STAFF-SA and WBD as they appears to be not in good agreement with WBD above 700 Hz while WBD/Whisper shows moderately good agreement. O. Santolik was in charge of this action, to be done during the summer.
Power spectrogram of the electric field fluctuations. (WBD) Power spectrogram of the magnetic field fluctuations. (STAFF-SA) Parallel component of the Poynting vector normalized by its standard deviation. (STAFF-SA) Electromagnetic planarity. (STAFF-SA) \// Bo SOURCE // Bo
ZOOM on SOURCE REGION WBD • Selected intervals of WBD magnetic-filed measurements 08:44:55- 8:53:48, • compared with the STAFF-SA onboard analyzed data • WBD • BY component in the spinning spacecraft system (10s ~every 50s when Whisper is active) • FFT of time series corresponding to STAFF-SA 4-s analysis intervals • Power is averaged in frequency intervals of 27 STAFF-SA frequency channels • STAFF-SA • despun sunward component, analyzed onboard
WBD and STAFF-SA data in 56 time intervals of 4 s and 27 freq. steps
STAFF-SA Band A But low power in band A
STAFF-SA Band C Best Better, but intense waves
A B C Low waves Strong waves Noise
Results • Large differences of obtained PSD at low frequencies < 60 Hz, probably linked to the WBD high-pass filters. -> low signal, and no same sensitivity • Median power ratio for f > 60 Hz is 1-5. STAFF-SA shows higher levels than WBD. (bands B & C) • Large variations (~one order of magnitude) • Very intense waves with PSD> 10-7 nT 2/Hz give similar values for STAFF-SA and WBD. • Proper comparison is difficult, WBD samples one single spinning component, STAFF-SA gives onboard despun data.