Proton temperature anisotropy and magnetic reconnection in the solar wind: effects of kinetic instabilities on current sheet stability

Abstract

We investigate the role of kinetic instabilities driven by a proton anisotropy on the onset of magnetic reconnection by means of 2-D hybrid simulations. The collisionless tearing of a current sheet is studied in the presence of a proton temperature anisotropy in the surrounding plasma. Our results confirm that anisotropic protons within the current sheet region can significantly enhance/stabilize the tearing instability of the current. Moreover, fluctuations associated to linear instabilities excited by large proton temperature anisotropies can significantly influence the stability of the plasma and perturb the current sheets, triggering the tearing instability. We find that such a complex coupling leads to a faster tearing evolution in a regime with larger perpendicular temperature when an ion-cyclotron instability is generated by the anisotropic proton distribution functions. On the contrary, in the presence of the opposite anisotropy, fire hose fluctuations excited by the unstable background protons with larger parallel temperature are not able to efficiently destabilize the current sheets, which remain stable for a long time after fire hose saturation. We discuss possible influences of this novel coupling on the solar wind and heliospheric plasma dynamics.

6 pages, 6 figures, Accepted for publication in the Astrophysical Journal

References in corpus (4)

• Intermittent Dissipation and Local Heating in the Solar Wind
• Kinetic Signatures and Intermittent Turbulence in the Solar Wind Plasma
• Local 2D Particle-in-cell simulations of the collisionless MRI
• HCN to HCO^+ Millimeter Line Diagnostics of AGN Molecular Torus I : Radiative Transfer Modeling

Cited by in corpus (15)

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• Models of magnetic-field evolution and effective viscosity in weakly collisional extragalactic plasmas
• Proton Kinetic Effects and Turbulent Energy Cascade Rate in the Solar Wind
• Fire Hose instability driven by alpha particle temperature anisotropy
• Multiple current sheet systems in the outer heliosphere: Energy release and turbulence
• The three-dimensional evolution of ion-scale current sheets: tearing and drift-kink instabilities in the presence of proton temperature anisotropy
• Instabilities of collisionless current sheets revisited: the role of anisotropic heating
• Onset of magnetic reconnection in a collisionless, high-beta plasma
• A Hamiltonian gyrofluid model based on a quasi-static closure
• Fire-hose instability of inhomogeneous plasma flows with heat fluxes
• Hybrid simulations of the proton beam instabilities in the young solar wind. The formation of hammerhead-like distributions
• Triggering tearing in a forming current sheet with the mirror instability