Anomalous resistivity in non-Maxwellian plasmas

Vlasov simulations of the current-driven ion-acoustic instability produced in Maxwellian and non-Maxwellian (Lorentzian, kappa = 2) electron-ion plasma with number density 7 x 10(6) cm(-3), reduced mass ratio m(i)/m(e) = 25, and electron to ion temperature ratio T-e/T-i = 1 are presented and compared. A concise stability analysis of current-driven ion-acoustic waves in Maxwellian and non-Maxwellian plasmas modeled by generalized Lorentzian distribution function with index 2 less than or equal to kappa less than or equal to 7 and electron to ion temperature ratio 1 less than or equal to T-e/T-i less than or equal to 100 is also presented. The ion-acoustic instability is excited in low temperature ratio Lorentzian (kappa = 2) plasma for lower absolute electron drift velocity (up to half the critical electron drift velocity of a Maxwellian). The anomalous resistivity resulting from ion acoustic waves in a Lorentzian plasma is a strong function of the electron drift velocity and in the work presented here varies by a factor of similar to100 for a 1.5 increase in the electron drift velocity. Furthermore, ion-acoustic anomalous resistivity is excited for electron drift velocities that would be stable for Maxwellian plasmas. The magnitude of resistivity which can be generated by unstable ion-acoustic waves may be important for magnetic reconnection at the magnetopause.

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