Resistive Tearing Mode Instability in Generalized Harris Current Sheets
The widely adopted initial force-balanced equilibrium prior to the occurrence of magnetic reconnection (MR) is the so-called Harris sheet model with antiparallel magnetic field. This study examines the tearing mode instability of the recently developed generalized Harris sheet equilibrium based on t...
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IOP Publishing
2025-01-01
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| Online Access: | https://doi.org/10.3847/1538-4357/add682 |
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| author | C.-K. Chang L.-N. Hau |
| author_facet | C.-K. Chang L.-N. Hau |
| author_sort | C.-K. Chang |
| collection | DOAJ |
| description | The widely adopted initial force-balanced equilibrium prior to the occurrence of magnetic reconnection (MR) is the so-called Harris sheet model with antiparallel magnetic field. This study examines the tearing mode instability of the recently developed generalized Harris sheet equilibrium based on two-dimensional, resistive, isotropic, linear, and nonlinear MHD models. The generalized Harris equilibrium incorporating the nonthermal Kappa-like velocity distributions in the Vlasov–Maxwell equations may give rise to a family of plasma and magnetic field profiles with various current layer thicknesses which may be used to study various plasma instabilities and MR. It is shown that the linear growth rate is proportional to ${\delta }^{-2/5}{R}_{m}^{-2/5}$ , where $\delta $ and ${R}_{m}$ are the current layer thickness and magnetic Reynolds number, respectively. The linear eigenmode solutions are used as the initial perturbations of the nonlinear MHD simulations to allow the full evolution of the tearing instability. It is shown that the cases with small ${R}_{m}$ may not be nonlinearly unstable, and the cases with relatively thinner current sheets and larger ${R}_{m}$ may grow faster with larger aspect ratios of magnetic islands. In the generalized kinetic Harris models, the thinning of current sheets may be achieved by the decrease of central temperature or the increase of the drift velocity of charged particles. The asymptotic magnetic field of the equilibrium profiles seems to play a minor role in the linear and nonlinear growth of resistive tearing mode instability. |
| format | Article |
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| institution | DOAJ |
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| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-57dd2b97636943b499993f3f0e0f0f752025-08-20T02:44:24ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01987215310.3847/1538-4357/add682Resistive Tearing Mode Instability in Generalized Harris Current SheetsC.-K. Chang0https://orcid.org/0000-0001-9051-6307L.-N. Hau1https://orcid.org/0000-0003-0002-3037Department of Space Science and Engineering, National Central University , Taoyuan City, Taiwan R.O.C.Department of Space Science and Engineering, National Central University , Taoyuan City, Taiwan R.O.C.; Department of Physics, National Central University , Taoyuan City, Taiwan R.O.C.The widely adopted initial force-balanced equilibrium prior to the occurrence of magnetic reconnection (MR) is the so-called Harris sheet model with antiparallel magnetic field. This study examines the tearing mode instability of the recently developed generalized Harris sheet equilibrium based on two-dimensional, resistive, isotropic, linear, and nonlinear MHD models. The generalized Harris equilibrium incorporating the nonthermal Kappa-like velocity distributions in the Vlasov–Maxwell equations may give rise to a family of plasma and magnetic field profiles with various current layer thicknesses which may be used to study various plasma instabilities and MR. It is shown that the linear growth rate is proportional to ${\delta }^{-2/5}{R}_{m}^{-2/5}$ , where $\delta $ and ${R}_{m}$ are the current layer thickness and magnetic Reynolds number, respectively. The linear eigenmode solutions are used as the initial perturbations of the nonlinear MHD simulations to allow the full evolution of the tearing instability. It is shown that the cases with small ${R}_{m}$ may not be nonlinearly unstable, and the cases with relatively thinner current sheets and larger ${R}_{m}$ may grow faster with larger aspect ratios of magnetic islands. In the generalized kinetic Harris models, the thinning of current sheets may be achieved by the decrease of central temperature or the increase of the drift velocity of charged particles. The asymptotic magnetic field of the equilibrium profiles seems to play a minor role in the linear and nonlinear growth of resistive tearing mode instability.https://doi.org/10.3847/1538-4357/add682Plasma physicsSpace plasmasPlanetary magnetospheresPlasma astrophysicsMagnetohydrodynamicsMagnetohydrodynamical simulations |
| spellingShingle | C.-K. Chang L.-N. Hau Resistive Tearing Mode Instability in Generalized Harris Current Sheets The Astrophysical Journal Plasma physics Space plasmas Planetary magnetospheres Plasma astrophysics Magnetohydrodynamics Magnetohydrodynamical simulations |
| title | Resistive Tearing Mode Instability in Generalized Harris Current Sheets |
| title_full | Resistive Tearing Mode Instability in Generalized Harris Current Sheets |
| title_fullStr | Resistive Tearing Mode Instability in Generalized Harris Current Sheets |
| title_full_unstemmed | Resistive Tearing Mode Instability in Generalized Harris Current Sheets |
| title_short | Resistive Tearing Mode Instability in Generalized Harris Current Sheets |
| title_sort | resistive tearing mode instability in generalized harris current sheets |
| topic | Plasma physics Space plasmas Planetary magnetospheres Plasma astrophysics Magnetohydrodynamics Magnetohydrodynamical simulations |
| url | https://doi.org/10.3847/1538-4357/add682 |
| work_keys_str_mv | AT ckchang resistivetearingmodeinstabilityingeneralizedharriscurrentsheets AT lnhau resistivetearingmodeinstabilityingeneralizedharriscurrentsheets |