彗星中尘埃的带电特性和平衡电势的研究  

STUDY ON THE CHARGING CHARACTERISTICS AND EQUILIBRIUM POTENTIAL OF DUST GRAINS IN COMETS

作　　者：陈耀[1] 李中元[1] 李嘉巍[1] 段素平[1] 

机构地区：[1]中国科学技术大学地球和空间科学学院,合肥230026

出　　处：《空间科学学报》2003年第5期329-333,共5页Chinese Journal of Space Science

基　　金：国家自然科学基金项目(10173010;49834040);中国科学院知识创新工程方向性项目共同资助

摘　　要：分析了彗星中尘埃粒子的带电特性,以及计算了彗星尘埃等离子体的典型参数.对Halley彗星和G—Z彗星进行了讨论,得出了彗星中尘埃平衡电势的一些主要规律.一般来说,这些规律也可以适用于其他等离子体彗星.The comets are consisted mainly of water and dust and around cometary nuclear there are ionized gases mainly made up of water and hydrogen. Dust grains in comet will become charged. As a new composition, charged dust grains will take part in cometary plasma group behaviors. Three main charging mechanisms are considered in this paper. First, charged plasma particles spray onto surfaces of dust grains will be collected, this current is presented by J1; second, photoemission caused by the solar rays, the photoelectron current is J2; third, J3, current of secondary electron eject. At a certain stage, dust grains will stop charging and attain an equilibrium-state, i.e., ∑ Jα = 0, α = 1,2,3. Considering that comets are plasma environments of H2O+, and the main compositions of cometary dust are silicate and carbon, based upon observational data of comet Halley and comet G-Z, the charging characteristics and equilibrium potentials of dust grains are calculated. A curve of equilibrium potential at different distance from the nuclear of P/Halley is provided. It is found that the equilibrium potential is obviously correlative with electron density. Using algebraic equations about equilibrium potential and logarithm of electron density, too, the calculations showed that the equilibrium potential has little relativity with other plasma parameters such as electron temperature. Generally, these conclusions can be suitable for other plasma comets.

关 键 词：G-Z彗星 尘埃粒子 带电特性 平衡电势 Halley彗星 充电 

分 类 号：P185.8[天文地球—天文学]