Структура и динамика полярных токовых систем : материалы международного симпозиума «Полярные геомагнитные явления», 25-31 мая, Суздаль, СССР / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Апатиты : [б. и.], 1988.

200 т 700 700 Т Т Г ] i m R T E D - V I PRECIPITATION I 400 200 К№ "Г NORTH | ZOmV/m ч !— -ERST 500 FLIGHT т/ме ($) 900 Fig, 1. DC electric field (top panel) and ac electric field fluctuations (bottom panel) along the CAESAR trajectory versus flight time or altitude. FL/ Ш TIME (S) ' The lower panel of Pig.1 shows the spectral content of the ac electric field parallel to the Earth magnetic field integrated over 10 Hz wide bands centered at 20, 40, 60, 80, 100, 120, and 140 Hz. The spectral data are obtained from consecutive spin periods. (The signal of each of these .65 s intervals was subjected to interval-centered Hanning and than Fourier trans formed (FFT).) The ac eignal is only observed south of the precipitation region between 200 s and 450 s flight time. The field components perpendicular to the mag n e tic field have amplitudes of less than one third of the amplitudes of the parallel fields but show very similar dependencies in frequency and time. During the second half of the flight some data g^ps occured because of tele metry errors. There is distinct anticorrelation between the intensity of the fluctuations and the particle flux equatorward the arc. The ac magnetometer on board the CAESAR payload did not receive corresponding magnetic fluctua tions, thus these signals are pure electrostatic (Dehmel, private communic ation, 1985). Synchronous with the CAESAR flight the EXSCAT-System observed the plasma drift at seven locations of a south-north scan at an altitude of 140 km. From such drift measurements electric fields can be deduced. Assuming that electron neutral collisions and neutral winds are negligible the electric field is derived from vbffl (v is the plasma drift velocity, S' is the Earth magnetic field). Figure 2 shows plasma drift velocity vectors at the 140 km altitude level in geographic coordinates. The squares labeled A - G indicate the locations where EISCAT measured the plasma drift at 140 km height. The dense sequence of vector arrows presents drift velocities calculated from CAESAR electric fields assuming EdT drift. The electric fields measured along the trajectory 90