On MHD waves, fire-hose and mirror instabilities in anisotropic plasmas
Temperature or pressure anisotropies are characteristic of space plasmas, standard magnetohydrodynamic (MHD) model for describing large-scale plasma phenomena however usually assumes isotropic pressure. In this paper we examine the characteristics of MHD waves, fire-hose and mirror instabilities in...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2007-09-01
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| Series: | Nonlinear Processes in Geophysics |
| Online Access: | http://www.nonlin-processes-geophys.net/14/557/2007/npg-14-557-2007.pdf |
| _version_ | 1830451465191161856 |
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| author | L.-N. Hau B.-J. Wang |
| author_facet | L.-N. Hau B.-J. Wang |
| author_sort | L.-N. Hau |
| collection | DOAJ |
| description | Temperature or pressure anisotropies are characteristic of space plasmas, standard magnetohydrodynamic (MHD) model for describing large-scale plasma phenomena however usually assumes isotropic pressure. In this paper we examine the characteristics of MHD waves, fire-hose and mirror instabilities in anisotropic homogeneous magnetized plasmas. The model equations are a set of gyrotropic MHD equations closed by the generalized Chew-Goldberger-Low (CGL) laws with two polytropic exponents representing various thermodynamic conditions. Both ions and electrons are allowed to have separate plasma beta, pressure anisotropy and energy equations. The properties of linear MHD waves and instability criteria are examined and numerical examples for the nonlinear evolutions of slow waves, fire-hose and mirror instabilities are shown. One significant result is that slow waves may develop not only mirror instability but also a new type of compressible fire-hose instability. Their corresponding nonlinear structures thus may exhibit anticorrelated density and magnetic field perturbations, a property used for identifying slow and mirror mode structures in the space plasma environment. The conditions for nonlinear saturation of both fire-hose and mirror instabilities are examined. |
| first_indexed | 2024-12-21T08:33:40Z |
| format | Article |
| id | doaj.art-0116f10a5dc64460bc82ab928e53a32e |
| institution | Directory Open Access Journal |
| issn | 1023-5809 1607-7946 |
| language | English |
| last_indexed | 2024-12-21T08:33:40Z |
| publishDate | 2007-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Nonlinear Processes in Geophysics |
| spelling | doaj.art-0116f10a5dc64460bc82ab928e53a32e2022-12-21T19:10:07ZengCopernicus PublicationsNonlinear Processes in Geophysics1023-58091607-79462007-09-01145557568On MHD waves, fire-hose and mirror instabilities in anisotropic plasmasL.-N. HauB.-J. WangTemperature or pressure anisotropies are characteristic of space plasmas, standard magnetohydrodynamic (MHD) model for describing large-scale plasma phenomena however usually assumes isotropic pressure. In this paper we examine the characteristics of MHD waves, fire-hose and mirror instabilities in anisotropic homogeneous magnetized plasmas. The model equations are a set of gyrotropic MHD equations closed by the generalized Chew-Goldberger-Low (CGL) laws with two polytropic exponents representing various thermodynamic conditions. Both ions and electrons are allowed to have separate plasma beta, pressure anisotropy and energy equations. The properties of linear MHD waves and instability criteria are examined and numerical examples for the nonlinear evolutions of slow waves, fire-hose and mirror instabilities are shown. One significant result is that slow waves may develop not only mirror instability but also a new type of compressible fire-hose instability. Their corresponding nonlinear structures thus may exhibit anticorrelated density and magnetic field perturbations, a property used for identifying slow and mirror mode structures in the space plasma environment. The conditions for nonlinear saturation of both fire-hose and mirror instabilities are examined.http://www.nonlin-processes-geophys.net/14/557/2007/npg-14-557-2007.pdf |
| spellingShingle | L.-N. Hau B.-J. Wang On MHD waves, fire-hose and mirror instabilities in anisotropic plasmas Nonlinear Processes in Geophysics |
| title | On MHD waves, fire-hose and mirror instabilities in anisotropic plasmas |
| title_full | On MHD waves, fire-hose and mirror instabilities in anisotropic plasmas |
| title_fullStr | On MHD waves, fire-hose and mirror instabilities in anisotropic plasmas |
| title_full_unstemmed | On MHD waves, fire-hose and mirror instabilities in anisotropic plasmas |
| title_short | On MHD waves, fire-hose and mirror instabilities in anisotropic plasmas |
| title_sort | on mhd waves fire hose and mirror instabilities in anisotropic plasmas |
| url | http://www.nonlin-processes-geophys.net/14/557/2007/npg-14-557-2007.pdf |
| work_keys_str_mv | AT lnhau onmhdwavesfirehoseandmirrorinstabilitiesinanisotropicplasmas AT bjwang onmhdwavesfirehoseandmirrorinstabilitiesinanisotropicplasmas |