Anomalous resistivity and heating in current-driven plasma thrusters

A theory is presented of anomalous resistivity and particle heating in curr ent-driven plasma accelerators such as the magnetoplasmadynamic thruster (M PDT). An electromagnetic dielectric tensor is used for a current-carrying, collisional and finite-beta plasma and it is found that an instability akin to the generalized lower hybrid drift instability (GLHDI) exists for elect romagnetic modes (i.e., with finite polarization). Weak turbulence theory i s then used to develop a second-order description of the heating rates of p articles by the waves and the electron-wave momentum exchange rate that con trols the anomalous resistivity effect. It is found that the electron Hall parameter strongly scales the level of anomalous dissipation for the case o f the MPDT plasma. This scaling has recently been confirmed experimentally [Phys. Plasmas 5, 3581 (1997)]. Polynomial expressions of the relevant tran sport coefficients cast solely in terms of macroscopic parameters are also obtained for including microturbulence effects in numerical plasma fluid mo dels used for thruster flow simulation. (C) 1999 American Institute of Phys ics. [S1070-664X(99)95705-1].