ORBIT LIMITED THEORY IN THE SOLAR WIND - κ DISTRIBUTIONS

Serbian Astronomical Journal

article

M. M. Martinovi´c¹ 

[1] LESIA;Department of Astronomy, Faculty of Mathematics, University of Belgrade Studentski trg 16;IHIS Techno-experts d.o.o. - Research and Development Center Batajnicki drum 23

关键词: plasmas;    Sun: solar wind;   

DOI  :  10.2298/SAJ160220004M

来源: Astronomical Observatory, Department of Astronomy, Belgrade

【 摘 要 】

When a solid object is immersed into ionized gas it gets brought to a certain value of electrostatic potential and surrounded by a space charge region called ‘plasma sheath’. Through this region, particles are attracted or repelled from the surface of the charge collecting object. For collisionless plasma, this process is described by the so-called orbit limited theory, which explains how the collection of particles is determined by the collector geometry and plasma velocity distribution function (VDF). In this article, we provide explicit orbit-limited currents expressions for generalized Lorentzian (κ) distributions. This work is useful to describe the charging processes of objects in non-collisional plasmas like the solar wind, where the electrons VDF is often observed to exhibit quasi power-law populations of suprathermal particles. It is found that these ‘suprathermals’ considerably increase the charge collection. Since the surface charging process that determines the value of electrostatic potential is also affected by the plasma VDF, calculation of the collector potential in the solar wind is described along with some quantitative predictions.

【 授权许可】

CC BY-NC-ND