VDP and CORALL instruments

Welcome to the VDP and CORALL home page.

VDP and CORALL are two of plasma instruments set of INTERBALL project. This home page contains:

Andrey Fedorov (af@afed.iki.rssi.ru)

2-D ION ENERGY SPECTROMETER CORALL

Yu.I.Yermolaev, A.O.Fedorov, O.L.Vaisberg, V.M.Balebanov, Yu.A.Obod

Space Research Institute, Russian Academy of Sciences, Russia

R.Jimenez, J.Fleites, L.Llera

Intercosmos, Republic Cuba

A.N.Omelchenko

Institute of Applied Geophysics, Russian Hydrometeorological Service, Russia

Description

Hemispherical electrostatic ion energy spectrometer CORALL has fan-shaped field-of-view of 10 x 150 degrees. Satellite rotation with period about 2 min enables one to perform quasi-3D measurements of Energy/Charge ion distribution function in the range from 30 to 24200 eV/q with good energy resolution. The accumulation time on 1 energy step is 1/1024-th of the satellite rotation period, i.e. about 100 msec, and the scan period of 1 energy spectrum (32 steps) is equal to about 4 min. The main technical features of instrument are presented in Table.

Technical Characteristics of Spectrometer CORALL

Instrument CORALL was designed and fabricated jointly by IKI RAN and INTERCOSMOS of Republic of Cuba.

Operation and Measurements

Since August 14, 1995 the instrument is working. However, there were any problems with system BNS which provides pulse of satellite rotation (The CORALL uses this pulse for performance of measurements in inercia coordinate system). Since August 31, 1995 the complex BNS + CORALL is operating properly.

The following picture shows measurements of ion energy spectra with 3 polar channels of instrument during magnetopause crossing on 19:52 UT October 18.

Click picture to get big one.

Please, send your comments to

OMNIDIRECTIONAL PLASMA SENSOR VDP

J. Safrankova, Z. Nemechek, M. Simerski, L. Prech

Faculty of Mathematics and Phisics of Charles University, Prague, Czech Republic

G. Zastenker, A.Fedorov, O. Vaisberg

Space Research Institute, Academy of Sciences of Russia, Moscow, Russia

Yu. Sharko, T. Romasenko

Design bureau AALAM, Bishkek, Kirgizstan

Description

 The VDP instrument was designed for determination of integral flux vector or integral energetic spectrum at the range 0.2 - 2.4 keV of ions or electrons of magnetospheric plasma. The instrument includes 6 identical Faraday caps, located by following ways:
Cap #1 is directed toward the Sun. It's main axis lies along axis of spacecraft rotation (+X).
Cap #6 has antisunward direction (-X).
Caps #2 - #5 are directed along +Y, +Z, -Y, -Z axes respectively. These axes rotate with spacecraft.

The figure shows cross-section of one Faraday cup.

Positive grid (C2) and negative grid (C3) is used to select ions or elecrons measurement. In case of constant voltage, sensor supplies the total flux of ions plus flux of electrons above 2400 eV energy, or total flux of electrons plus flux of ions above 2400 eV energy. To get ion or electron spectra the voltage of C2 or C3 is changed step by step over 16 steps in range 0 - 2400 V. Cup #1 does not have negative grid and supplies the ion flux plus electron flux with energy more then 170eV.

The maximum of data rate is 16 sample per second. In case of spectra measuring one step is held during one second and full spectrum takes 16s.

The output range of direct current amplifier is -6.0 - + 6.0 V. The flux can be calculated by : 


                   P = 0.43E+9 1/cm*cm*s/V

The minimal digitased flux is 6.0E+5 1/cm*cm*s
and the maximum flux is 2.6E+9 1/cm*cm*s.

Operation and Measurements

VDP instrument works since August 14, 1995. Two Faraday caps #4 and #6 have problems and are not developed now.

Following pictures demonstrates instrument perfomance:

The example of magnetopause crossing on October 9.
Click picture to get big one.

Please, send your comments to

The Latest VDP and CORALL Data

Sorry, the page is under construction yet.