Fundamental technical development of the detector system of the solar resonance scattering light by analyzing the ion density and velocity distribution

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We studied the possibility to image the oxygen ions which exist in the Earth's magnetotail. As we had had no knowledge of the existence of the oxygen ions in the tail region of the Earth's magnetosphere until several years before, the GEOTAIL spacecraft, which serches for the magnetosphere, identified the oxygen ions with very low temperature and high density. These oxygen ions flow as a beam from the Earth to the tail direction, whose velocity becomes higher as more distant. We will make big progress in studying the dynamics of the magnetosphere, if we can take picutres of the whole magnetosphere by using oxygen ions. The wavelength of the resonant scattering light is subject to the Doppler shifting, as the oxygen ions move relatively to the Sun. The efficiency of the resonant scatter becomes worse when ions are largely Doppler shifted because the width of the resonant scattering lines is several tens of milli-angstrom and the emission line width of the sun light is the same order to … More this. Resonant scatter does not occur essentially to the single emission line as helium, when relative velocity becomes over 50km/sec. Oxygen ions, on the other hand, have three resonant scattering lines which are very close to each other. There are 9 emission lines corresponding to the (singly and doubly ionized) oxygen ion in the solar light, so Oxygen ions can scatter another emission line resonantly when they are subjected to the Doppler shifting by the relative motion. We calculated the geometric factor which show the efficiency of the resonant scatter considering this effect. Also, we simulated the intensity of the scattered light from the tail region of the magnetosphere by the oxygen ions by using the model of the velocity, temperature and density of the oxygen ions from the results of the GEOTAIL spacecraft. Using these values, we concluded that the intensity of the light is 0.1-10 Rayleigh. The result means that we can image the Earth's magnetosphere with the resolution of 1 Re (Earth's radius) by using 25 cm diameter telescope, exposing about 10 minutes. Thus our study show the imaging of the magnetotail is possible in principle. Less