Open AccessTEARING MODES GROWTH RATE AMPLIFICATION DUE TO FINITE CURRENT RELAXATION
Author(s) -
F. E. M. Silveira
Publication year - 2017
Publication title -
acta polytechnica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.207
H-Index - 15
eISSN - 1805-2363
pISSN - 1210-2709
DOI - 10.14311/ap.2017.57.0032
Subject(s) - tearing , physics , wavelength , electron , limiting , plasma , ohm , current density , condensed matter physics , relaxation (psychology) , limit (mathematics) , electrical resistivity and conductivity , magnetic field , ohm's law , magnetic reconnection , long wavelength limit , quantum electrodynamics , work (physics) , atomic physics , quantum mechanics , thermodynamics , mechanical engineering , psychology , social psychology , mathematical analysis , mathematics , engineering
In this work, we explore the influence of perturbative wavelengths, shorter than those usually considered, on the growth rate γ of the tearing modes. Thus, we adopt an extended form of Ohm’s law, which includes a finite relaxation time for the current density, due to inertial effects of charged species. In the long wavelength limit, we observe the standard γ of the tearing modes. However, in the short wavelength limit, we show that γ does not depend on the fluid resistivity any longer. Actually, we find out that γ now scales with the electron number density n e as γ ~ n e −3/2 . Therefore, through a suitable combination of both limiting results, we show that the standard γ can be substantially amplificated, even by moderate shortenings of perturbative wavelengths. Further developments of our theory may contribute to the explanation of the fast magnetic reconnection of field lines, as observed in astrophysical plasmas.