Scientific program

Characteristics of the regions crossed by the satellites

Research objects and scientific purposes

Space scientific program includes development and launch of two supersmall spacecrafts "Universitetskiy" and "Kompas-2" intended for monitoring of radiation conditions near the Earth. Calculated orbits of the spacecrafts are 1000 and 500 km, correspondingly.

Due to high inclination of the orbits the satellites will cross all the main structural regions of the Earth magnetosphere: radiation belts, auroral zone and polar caps, providing a basis for fundamental and applied research in these regions, which are essentially differ in their characteristics phenomena.

Characteristics of the regions crossed by the satellites

All the studies conducted in the near-Earth space are characterised by strong radiation fields. Up to the latitudes of ~65° they are formed by the Earth radiation belts, and at the higher latitudes - by the solar cosmic rays produced during the solar flares.

The circular polar orbits, which cover all the near-Earth space, are the most favorable for comprehensive studies of the radiation conditions near the Earth.

Earth radiation belts generally consist of protons within the energy range of 0.1 – 1000 MeV and flux density of up to 10⁷ cm^–2s^–1 (at ~0.1 MeV energy) and electrons within the energy range of 0.04 – 10 MeV with flux density of up to 10⁸ cm^–2s^–1 (at ~0.04 MeV energy).

Spatial and energetic distributions of the radiation belts particles in the near-Earth space are heterogeneous and depend both on the structure and the value of the geomagnetic field, and on the generation and losses mechanisms in the geomagnetic trap region.

The most strict radiation is concentrated in the region of geomagnetic equator at the altitudes of up to 3000 km. Just this altitude is characterized by presence of the Earth radiation belts' protons with energy up to ~1000 MeV.

Supersmall satellites "Universitetskiy" and "Kompas-2" will cross the spurs of the Earth radiation belts at low altitudes and pass near the center of the inner radiation belt at the equator. The great bulk of the high-energy particles is concentrated in the southern hemisphere in the region of South Atlantic near Brazil. Well-known longitudinal dependence of radiation dose (during a circuit) up to 10⁴ is conditioned by asymmetric distribution of the Earth radiation belts at low altitudes due to longitudinal asymmetry of the Earth magnetic field. The spacecrafts are exposed to the maximum radiation dose crossing the region of South Atlantic near Brazil. Protons of the solar cosmic rays (solar flares) are concentrated near the geomagnetic poles at high geomagnetic latitudes. The higher is the energy of the protons the lower are the latitudes they penetrate and the wider and the longer is the zone of their influence on the spacecraft.

Radiation conditions in the near-Earth space is generally determined by the solar activity. The launches and the active life periods of the satellites fall on the decay (and probably minimum) phase of the solar activity cycle 23. During this period solar flares are not often, but still possible. Most likely 1 or 2 solar active regions will entail recurrent geomagnetic disturbances in the Earth magnetosphere. Such situation allows to observe "pure" phenomena without superposition of different events.

Solar activity has double influence on radiation conditions:

1)	energy particles themselves (mainly protons), which come to the Earth after the solar flares;
2)	geomagnetic disturbances (magnetic storms) in the magnetosphere, during which powerful flows of high-energy particles are generated due to intramagnetospheric acceleration processes, which lead in particular to the formation of the Earth radiation belts.

In spite of common genetic connections between all the geophysical phenomena and solar activity, specific plasma processes, which take place in different regions of the magnetosphere, are different. It provides a basis to separate the near-Earth space with regular magnetic field into four regions:

1)	polar caps;
2)	auroral refions;
3)	outer radiation belt;
4)	inner radiation belt.

The orbits of the developed spacecrafts will regularly cross all these regions, both in nothern and in southern hemispheres. It provides a basis separate all the experimental purposes into four groups. Moreover it is planned for each structural region of the magnetosphere to obtain experimental results, which provide clear physical interpretation within the framework of generally accepted theoretical conceptions. This approach will allow to interpret the results of the experiment not only qualitively, but also quantatively.-->

Research objects and scientific purposes

1.	Polar cap
	1.	Forbush-effect of galactic cosmis rays (GCR).
	2.	Latitudinal effect of GCR.
	3.	Flare increases of solar cosmic rays (SCR).
	4.	Dynamics of the SCR's penetration boundaries.
	5.	Topology of remote regions of the magnetosphere.

2.	Auroral region
	Dynamics of the auroral region boundaries by means of observation of:
	–	electrons with energy of ~ 1 keV;
	–	electrons with energy of >70 keV;
	–	SCR protons with energy of ~1 MeV;
	–	atmospheric glow at λ = 3914Å.

3.	Outer radiation belt
	1.	Studies of the outer belt structure under the quiet and disturbed geomagnetic conditions.
	2.	Studies of injection of electrons with energy of <300 keV.
	3.	Studies of injection mechanism of relativistic electrons (еЕ>1 MeV) during the geomagnetic storms.
	4.	Studies of electrons precipitation processes.

4.	Inner radiation belt
	1.	Studies of spatial distribution of high-energy protons.
	2.	Determination of the top boundary of relativistic electrons' fluxes.
	3.	Studies of the role of resonance mechanisms in the acceleration of high-energy electrons.

5.	Studies of UF variations
	1.	Aurora borealis and other atmospheric glows, caused by charged particles fluxes, penetrated into the Earth's atmosphere.
	2.	Atmospheric glow during electric discharges.
	3.	Meteors' glowing.
	4.	Measurments of UF glowing background in the atmosphere.

©Skobeltsyn Institute of Nuclear Physics, 2003 - 2005.