The Bohm criterion in a dusty plasma containing nonextensively distributed electrons and cold ions is investigated within the framework of probe model including the effects of dustcharge fluctuation. It is shown that the critical Mach number upshifts with the decrease of electron nonextensive parameter (qe) and the increase of the ion-to-electron number density ratio (Rn) when the effects of dustcharge fluctuation are out of consideration. Once the effects of dustcharge fluctuation are included, with the increase of Rn, the critical Mach number increases first, then decreases. The slop of the critical Mach number curves in the region for becomes more gradual than that for . When critical Mach number is defined with respect to modified ion acoustic wave speed, it should be larger than unity in the case free of dustcharge fluctuation. Whereas when , it may be smaller than unity due to the effect of dustcharge fluctuation.
Received 10 November 2012Accepted 13 March 2013Published online 02 April 2013
We are grateful to the anonymous referee whose comments greatly improved this article. This work was supported by the National Natural Science Foundation of China (Nos. 11178002 and 11247221), the Specialized Research Fund for the Doctoral Program of Higher Education (No. 20113601110007), the Scientific & Technological Innovation Research Fund of Jiangxi Province (No. 20114ACB00900), the Universities Natural Science Research Project of Jiangsu Province (No. 11KJB140006), and the Natural Science Foundation of Nantong University (Nos. 10ZY001, 11ZY022, and 12ZY004).
Article outline: I. INTRODUCTION II. DERIVATION OF THE BOHM CRITERION IN A DUSTY PLASMA WITH NONEXTENSIVE ELECTRONS A. Nonextensive distribution of electrons B. Electrostaticsheath in the model of cold ions and immobile dustgrains with charge variation C. Effects of charge variation induced by cold drift ions and nonextensive electron on Bohm criterion D. Two special limits III. NUMERICAL RESULTS IV. DISCUSSIONS AND CONCLUSIONS