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M. M. Molodensky 《Solar physics》1973,28(2):465-475
At present data exist showing that in some regions of the corona the polarization degree has been found to be higher than the maximum possible value determined by Thomson scattering. Besides this, there exist regions where the direction of the prevailing vibration of the E-vector does not coincide with the tangential one. This may be caused by the velocity of scattered electrons. The theory of polarization taking the velocity into account is given, and the above-mentioned data are discussed. The direction of polarization turns out to be the sensitive detector of fact electrons (for energy of 5 keV, the deviation angle 10°).Very important data about accelerated electrons on the Sun may be received from precise measurements of the corona polarization. 相似文献
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Sergey M. Molodensky 《Geophysical Journal International》1989,97(3):459-469
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Force-free magnetic fields (f.f.f) are considered as the first approximation of magnetic hydrodynamic equations in the case when the energy of the field exceeds the thermal energy of the medium. Such a relation of energies takes place in the upper atmosphere of the Sun in active regions.The consequence of the virial theorem obtained shows that for any solution of the corresponding non-linear system of equations only two cases are possible: either the total energy of the field is given by a divergent integral, or in some regions the force-free character of field is destroyed. This permits the conclusion that it is impossible to build f.f. current systems everywhere, and therefore boundary problems for this type of fields are of the same importance as for harmonic fields.Integral relations are obtained which are the necessary conditions for the solution of boundary problems. According to the classical principle of Thompson the harmonic fields are always stable, while f.f.f. may be stable or unstable.It is shown that: (1) arbitrary f.f.f. are stable to small changes of boundary conditions; (2) among f.f.f. the hydrodynamically stable configurations exist.The hydrodynamic stability condition restricts the size of force-free currents in such configurations. 相似文献
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