It is shown that ion acoustic waves in plasmas with ${\mathbf{E}}_0\times {\mathbf{B}}_0$ electron drift become unstable due to the closure of plasma current in the chamber wall. Such unstable modes may enhance both near-wall conductivity and turbulent electron transport in plasma devices with ${\mathbf{E}}_0\times {\mathbf{B}}_0$ electron drift and unmagnetized ions. It is shown that the instability is sensitive to the wall material: a high value of the dielectric permittivity (such as in metal walls) reduces the mode growth rate by an order of magnitude but does not eliminate the instability completely.

• Received 4 May 2013

DOI:https://doi.org/10.1103/PhysRevLett.111.115002