The name of the project APEX is a reduction from words " Active Plasma
Experiments " . The core of the project are active experiments with injection
of electron and (or) plasma beams from a board of the satellite with simultaneous
registration of the phenomena, produced by interaction of injected beam
with background plasma.
Essentially important peculiarity of the project are synchronous measurements
of the basic physical parameters of the environment,of the beam and generated
fields on two space separated vehicles - main satellite APEX and subsatellite
MAGION-3 . An independent subsatellite with adjusting truster installation
allows to carry out simultaneously measurements on various mutual distances
(from 0,01 up to 1000-2000 km), at different areas of disturbed environment
and propagation of a beam, at different zones of a magnetosphere and ionosphere.
The speed and distance of separation both spacecrafts are controlled by
small neutral gas trusters on the MAGION-3. The "boomerang" maneuvers of
MAGION-3 were performed few times: it was pushed forward and returns backward
to main satellite , so MAGION-3 escaped from the main APEX up to few hundreds
km and came back at distance about 0,4 km.
The important part of the program are researches natural and human made
of the phenomena in a passive mode. The presence of two spacecrafts, equipped
practically by equivalent complexes of the scientific equipment, enables
not only to carry out diverse researches of the ionosphere and bottom magnetosphere,
but also to distinguish spatial and temporary structure of the observable
The complex program of "under satellite" ground observation and experiments
includes standard geophysical monitoring and special programs with heating
Both spacecrafts, basic APEX and subsatellite MAGION-3,were launched
on an elliptical orbit with apogee of 3050 km and perigee of 440 km, with
the inclination 82,5 of a plane of an orbit (almost the polar orbit allows
to carry out researches in auroral area).
Primary scientific objectives
of the project
The most important problems of the project are:
research of wave radiation of a modulated beam of electrons, generation
of whistlers by a beam of electrons in the vicinity of injector and in
the region of geomagnetic equator;
research of dynamics and relaxation of electron and plasma beams in the
research of processes of charging of space vehicles and its neutralization;
research of excitation of magnetohydrodynamic and low-frequency waves in
the ionosphere by a modulated plasma beam and connected to it phenomenon
of a stimulated precipitation of trapped particles;
research of the nature of electrodynamic connection of electromagnetic
waves in the magnetosphere and ionosphere;
search of nonlinear wave structures as electromagnetic solitons in the
disturbed ionosphere; creation and study of strong local perturbations
of magnetospheric plasm, asuch as double layers and shock waves;
study of the transformation of waves in a strongly non-uniform plasma,
in particular of ballistic effects in wave barriers transparency;
research of processes of transformation of energy in the << solar
wind - magnetosphere - ionosphere >> system .
of APEX project
The diagnostic part of the set of scientific equipment of APEX represents
a complete set of scientific devices, allowing to carry out measurements
of micro- and macroparameters of thermal and suprathermal plasma components,
to measure space-energy distribution of particles, electric and magnetic
fields, analyse variable and constant electromagnetic fields and radiations,
measure optical emissions.
The important peculiarity of APEX is the presence of a subsatellite
MAGION, equipped by its own complex of scientific equipment, which
have practically the same opportunities to a plasma and fields measurements
as the main one.
Active experiments utilise modulated electron beam accelerator and source
of modulated xenon plasma beam on the main spacecraft APEX. The choice
of the parameters of the electron accelerator was determined by that in
different magnetic force tubes and at different heights. Various resonant
conditions for the interaction of waves with beams are available. As is
known from rocket experiments, resonant conditions can be used more effectively
if the beam is previously modulated at the resonant frequency.
Except the active means and diagnostic equipment APEX also includes
an additional ( to the basic configuration of the spacecraft) telemetry
system STO-AP,which was developed by the experts of Hungary, former USSR,
Poland and Czech republic.. The system STO-AP provides the interface for
the devices, management of modes of operations, preliminary processing
of the scientific information, independent control of onboard experiments,
formation of the TM-frames and transfer of the telemetry information to
the groundbased stations at Czech Republic, Russia and Germany.