Impulsive chromospheric heating of two-ribbon flares by the fast reconnection mechanism

Ugai, M.
March 2008
Physics of Plasmas;Mar2008, Vol. 15 Issue 3, p032902
Academic Journal
Chromospheric heating of two-ribbon flares is quantitatively studied for different values of R0, the ratio of the chromospheric plasma density to the coronal one, on the basis of the spontaneous fast reconnection model. In general, occurrence of impulsive chromospheric joule heating is delayed for the larger R0 because of more Alfvén traveling time in the chromosphere. Once the chromospheric heating occurs, the temperature becomes more than 30 times its initial value for the case of R0=400 in a pair of layers of deep chromosphere, and the region of high temperature shifts upward and becomes broader with time, since the chromospheric thin layer of joule heating shifts upward according to a pileup of reconnected field lines in the flare loop; then, chromospheric evaporation grows and extends outward, and its velocity becomes comparable with the coronal downflow velocity inside the loop boundary. The impulsive chromospheric heating is caused by drastic evolution of the flare current wedge, through which some part of the coronal sheet current suddenly turns its direction to be concentrated into the chromospheric thin layer; simultaneously, a magnetohydrodynamic (MHD) generator arises ahead of the flare loop top to provide a new current circuit inside the large-scale flare current wedge. Hence, it is concluded that the powerful MHD generator, sustained by the fast reconnection jet, drives the flare current wedge to evolve, leading to the impulsive chromospheric heating.


Related Articles

  • Drift solitons and shocks in inhomogeneous quantum magnetoplasmas. Haque, Q.; Mahmood, S. // Physics of Plasmas;Mar2008, Vol. 15 Issue 3, p034501 

    Linear and nonlinear drift waves are studied in inhomogeneous electron-ion quantum magnetoplasma with neutrals in the background. The Korteweg–de Vries–Burgers equation is derived by using the quantum hydrodynamic model for nonlinear drift waves with quantum corrections. Both...

  • The plasma properties of the solar upper atmosphere determined from high resolution observations... Feldman, Uri // Physics of Plasmas;May94, Vol. 1 Issue 5, p1390 

    Describes the plasma properties of the upper solar atmosphere, a domain that, when flares are included, encompasses about three orders of magnitude in temperature. Simulation of observed properties by a model consisting of electric currents flowing along magnetic field lines.

  • Two-dimensional plasma expansion in a magnetic nozzle: Separation due to electron inertia. Ahedo, Eduardo; Merino, Mario // Physics of Plasmas;Aug2012, Vol. 19 Issue 8, p083501 

    A previous axisymmetric model of the supersonic expansion of a collisionless, hot plasma in a divergent magnetic nozzle is extended here in order to include electron-inertia effects. Up to dominant order on all components of the electron velocity, electron momentum equations still reduce to...

  • Fast collisionless reconnection in electron-positron plasmas. Bessho, Naoki; Bhattacharjee, A. // Physics of Plasmas;May2007, Vol. 14 Issue 5, p056503 

    Magnetic reconnection in electron-positron (pair) plasmas is studied by two-dimensional, electromagnetic, particle-in-cell simulations. In pair plasmas, the Hall current does not appear because there is no scale separation between ion and electron motion. Simulations show that fast reconnection...

  • The dynamics of electron and ion holes in a collisionless plasma. Eliasson, B.; Shukla, P. K.; McKenzie, J. F. // Nonlinear Processes in Geophysics;2005, Vol. 12 Issue 2, p269 

    We present a review of recent analytical and numerical studies of the dynamics of electron and ion holes in a collisionless plasma. The new results are based on the class of analytic solutions which were found by Schamel more than three decades ago, and which here work as initial conditions to...

  • Kinetic slow mode-type solitons. K. Baumg�rtel, K.; Sauer, K.; Dubinin, E.; B�chner, J. // Nonlinear Processes in Geophysics;2005, Vol. 12 Issue 2, p291 

    One-dimensional hybrid code simulations are presented, carried out in order both to study solitary waves of the slow mode branch in an isotropic, collisionless, medium-� plasma (�i=0.25) and to test the fluid based soliton interpretation of Cluster observed strong magnetic depressions...

  • Experimental study of a radial plasma source. Makrinich, G.; Fruchtman, A. // Physics of Plasmas;Apr2009, Vol. 16 Issue 4, p043507 

    A radially outward acceleration of plasma in cylindrical geometry along an applied electric field and across an axial magnetic field is studied. The configuration, coined a radial plasma source, consists of two ceramic disks positioned parallel to each other, between which a cylindrical...

  • Resolving velocity space dynamics in continuum gyrokinetics. Barnes, M.; Dorland, W.; Tatsuno, T. // Physics of Plasmas;Mar2010, Vol. 17 Issue 3, p032106 

    Many plasmas of interest to the astrophysical and fusion communities are weakly collisional. In such plasmas, small scales can develop in the distribution of particle velocities, potentially affecting observable quantities such as turbulent fluxes. Consequently, it is necessary to monitor...

  • Measurement of correlation-enhanced collision rates using pure ion plasmas. Anderegg, F.; Driscoll, C. F.; Dubin, D. H. E.; O'Neil, T. M. // Physics of Plasmas;May2010, Vol. 17 Issue 5, p055702 

    This paper presents the first direct experimental measurements of the Salpeter enhancement of collisions due to particle correlations. The perpendicular-to-parallel collision rate ν⊥∥ is measured in laser-cooled pure ion plasmas, spanning the regimes from weak to strong...


Read the Article


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

Try another library?
Sign out of this library

Other Topics