Reduced fluid-kinetic equations for low-frequency dynamics, magnetic reconnection, and electron heating in low-beta plasmas

Zocco, Alessandro; Schekochihin, Alexander A.
October 2011
Physics of Plasmas;Oct2011, Vol. 18 Issue 10, p102309
Academic Journal
A minimal model for magnetic reconnection and, generally, low-frequency dynamics in low-beta plasmas is proposed. The model combines analytical and computational simplicity with physical realizability: it is a rigorous limit of gyrokinetics for plasma beta of order the electron-ion mass ratio. The model contains collisions and can be used both in the collisional and collisionless reconnection regimes. It includes gyrokinetic ions (not assumed cold) and allows for the topological rearrangement of the magnetic field lines by either resistivity or electron inertia, whichever predominates. The two-fluid dynamics are coupled to electron kinetics-electrons are not assumed isothermal and are described by a reduced drift-kinetic equation. The model, therefore allows for irreversibility and conversion of magnetic energy into electron heat via parallel phase mixing in velocity space. An analysis of the exchanges between various forms of free energy and its conversion into electron heat is provided. It is shown how all relevant linear waves and regimes of the tearing instability (collisionless, semicollisional, and fully resistive) are recovered in various limits of our model. An efficient way to simulate our equations numerically is proposed, via the Hermite representation of the velocity space. It is shown that small scales in velocity space will form, giving rise to a shallow Hermite-space spectrum, whence it is inferred that, for steady-state or sufficiently slow dynamics, the electron heating rate will remain finite in the limit of vanishing collisionality.


Related Articles

  • Numerical investigation of a compressible gyrofluid model for collisionless magnetic reconnection. Comisso, L.; Grasso, D.; Tassi, E.; Waelbroeck, F. L. // Physics of Plasmas;Apr2012, Vol. 19 Issue 4, p042103 

    Ion Larmor radius effects on collisionless magnetic reconnection in the presence of a guide field are investigated by means of numerical simulations based on a gyrofluid model for compressible plasmas. Compressibility along the magnetic field is seen to favour the distribution of ion guiding...

  • The onset of magnetic reconnection in three dimensions. Pritchett, P. L. // Physics of Plasmas;Aug2013, Vol. 20 Issue 8, p080703 

    The onset of collisionless magnetic reconnection in current sheets containing a localized enhancement of the initial normal magnetic field component is examined using 2D and 3D particle-in-cell simulations that treat a closed system. In the 2D case, the current sheet is found to remain stable...

  • The island coalescence problem: Scaling of reconnection in extended fluid models including higher-order moments. Jonathan Ng; Yi-Min Huang; Hakim, Ammar; Bhattacharjee, A.; Stanier, Adam; Daughton, William; Liang Wang; Germaschewski, Kai // Physics of Plasmas;215, Vol. 22 Issue 11, p1 

    As modeling of collisionless magnetic reconnection in most space plasmas with realistic parameters is beyond the capability of today's simulations, due to the separation between global and kinetic length scales, it is important to establish scaling relations in model problems so as to...

  • Electron response to collisionless magnetic reconnection. Perona, A.; Eriksson, L.-G.; Grasso, D. // Physics of Plasmas;Apr2010, Vol. 17 Issue 4, p042104 

    A gyrokinetic test particle code, based on a relativistic Hamiltonian guiding-center formulation, has been developed in order to investigate the behavior of an electron population during a collisionless magnetic reconnection event. The reconstruction of the electron distribution function allows...

  • The inner structure of collisionless magnetic reconnection: The electron-frame dissipation measure and Hall fields. Zenitani, Seiji; Hesse, Michael; Klimas, Alex; Black, Carrie; Kuznetsova, Masha // Physics of Plasmas;Dec2011, Vol. 18 Issue 12, p122108 

    It was recently proposed that the electron-frame dissipation measure, the energy transfer from the electromagnetic field to plasmas in the electron's rest frame, identifies the dissipation region of collisionless magnetic reconnection [Zenitani et al., Phys. Rev. Lett. 106, 195003 (2011)]. The...

  • Comparison of multi-fluid moment models with particle-in-cell simulations of collisionless magnetic reconnection. Liang Wang; Hakim, Ammar H.; Bhattacharjee, A.; Germaschewski, K. // Physics of Plasmas;2015, Vol. 22 Issue 1, p1 

    We introduce an extensible multi-fluid moment model in the context of collisionless magnetic reconnection. This model evolves full Maxwell equations and simultaneously moments of the Vlasov-Maxwell equation for each species in the plasma. Effects like electron inertia and pressure gradient are...

  • Collisionless magnetic reconnection in a plasmoid chain. Markidis, S.; Henri, P.; Lapenta, G.; Divin, A.; Goldman, M. V.; Newman, D.; Eriksson, S. // Nonlinear Processes in Geophysics;2012, Vol. 19 Issue 1, p145 

    The kinetic features of plasmoid chain formation and evolution are investigated by two dimensional Particlein-Cell simulations. Magnetic reconnection is initiated in multiple X points by the tearing instability. Plasmoids form and grow in size by continuously coalescing. Each chain plasmoid...

  • Collisionless magnetic reconnection in the presence of a sheared velocity field. Faganello, M.; Pegoraro, F.; Califano, F.; Marradi, L. // Physics of Plasmas;Jun2010, Vol. 17 Issue 6, p062102 

    The linear theory of magnetic field lines reconnection in a two-dimensional configuration in the presence of a (Kelvin–Helmholtz stable) sheared velocity field is investigated within a single fluid model, where the onset of magnetic field line reconnection is made possible by the effect...

  • Magnetic reconnection during collisionless, stressed, X-point collapse using particle-in-cell simulation. Tsiklauri, D.; Haruki, T. // Physics of Plasmas;Nov2007, Vol. 14 Issue 11, p112905 

    Magnetic reconnection during collisionless, stressed, X-point collapse was studied using a kinetic, 2.5D, fully electromagnetic, relativistic particle-in-cell numerical code. Two cases of weakly and strongly stressed X-point collapse were considered. Here the descriptors “weakly” and...


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics