Solar forced variations of terrestrial high energy particle environment as seen by RESIK PIN detectors on CORONAS-F

M. Kowalinski¹ , Z. Kordylewski¹, J. Sylwester¹, W. Trzebinski¹
, D. Lisin²

?? and in revised form ??

Abstract

RESIK is the bent crystal spectrometer aboard the CORONAS-F satellite. It is equipped with four PIN diode detectors. These detectors were used in order to detect background counts due to energetic particle contamination present within polar regions and SAA belts. At altitudes above 300 km (Coronas-F altitude is about 500 km) the population of charged particles trapped by the Earth's magnetic field consists of protons (energies between 100 keV and several hundred MeV) and electrons (energies between few tens of keV and 10 MeV). The construction of RESIK PIN diode detectors allows to sense particles with the energy above 1 MeV. We present diagrams illustrating the coupling of the Coronas-F particle environment and selected indicators of solar activity. The data shown have been collected during initial phase of mission.

1 Introduction

Variations of certain forms of SOLAR activity such as : solar wind, flares , coronal mass ejection, disappearing filaments, coronal holes, magnetic fields, can cause disturbances in Earth magnethosphere. These disturbances are especially noticeable in polar regions and possibly in the South Atlantic Anomaly (SAA). The SAA is the region of lower geomagnetic field. In this zone, which extends up to low Earth orbit (LEO) altitudes, the particle flux is significantly increased. In the SAA region the LEO satellites including ISS and shuttles, can be exposed to harmfull radiation. Polar cap regions are also dangerous to the health of unmanned satellite systems. In order to detect regions and times where/when the high voltage in RESIK proportional detectors should be switched off (to prevent problems), we use PIN diode sensors placed within the instrument.

Figure

Figure 1: The comparison of PIN sensors rate with MKL and with Goes10 X-radiation fluxes, Map covering monthly time interval.

2 Observation and results

The PIN sensors collected data from September 2001 to September 2003. We have found the best correlation (R = 0.97, left part of the Figure) between PIN sensor rates and MKL proton rates (Ep > 26 MeV). Time variations of RESIK PIN fluence, divided into three geographically separate subsets (South polar, SAA and North polar regions) are shown in the middle. The map shows the area of higher PIN rates as seen in May 2002. In both polar regions, increased PIN fluence appears related with certain flares (red curve, GOES X-rays).

3 Summary

Both polar regions energetic particle fluxes appear to be correlated with increased solar particle emission associated with certain flares. SAA region shows up also some activity-associated variability, however with a smaller amplitude and the maximum somewhat delayed in time with respect to polar regions’ maxima. The maximum fluctuations in the particle rate recorded within SAA is by factor of 10, few times the average rate. The observed SAA changes affect all LEO satellites including ISS.

RESIK is a common project between NRL (USA), MSSL and RAL (UK), IZMIRAN (Russia) and SRC (Poland). (PI - J. Sylwester). M.K., Z.K., J.S. and W.T. acknowledge support from grant 2.P03D.002.22 of the Polish Committee for Scientific Research.

References

[]: Norman A. Dyson 1978 X-rays in atomic and Nuclear physics.

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