Particle acceleration asymmetry in a reconnecting non-neutral current sheet

Valentina Zharkova ,  Bradford University

Electrons and protons acceleration caused by a super-Dreicer electric field directed along the longitudinal component $B_y$
     of magnetic field is investigated. The three-component magnetic field in a non-neutral current sheet occurring at the top of
    the reconnecting flaring loops on the charged particle trajectories and energies is considered. Particle trajectories in
    reconnecting current sheet and their energy spectra at the
    point of ejection from the reconnecting current sheet (RCS) are simulated from the motion equation for different sheet
    thicknesses.
    A super-Dreicer electric field of the current sheet is found to accelerate particles to coherent
    energy spectra in a range of 10 - 100 keV for electrons and 100-400 keV for protons with energy slightly increasing
    with the sheet thickness. A longitudinal $B_y$-component was found to define the gyration directions of particles
    with opposite charges towards the RCS midplane, i.e. the trajectory symmetry. For the ratio $B_y/B_z < 10^{-6}$ the
    trajectories are fully symmetric that results in particle ejection from a RCS as neutral beams. For the ratio
    $B_y/B_z > 10^{-2}$ the trajectories completely loose their symmetry towards the RCS midplane leading to the separation
    of particles with opposite charges into the opposite halves from a RCS midplane and the following ejection into
    different legs of the reconnecting loops. For the intermediate values of $B_y/B_z$ the trajectories are partially
    symmetric towards the midplane leading to electrons prevailing in one leg and protons in the other.