title: Stochastic threshold for ion heating with beating electrostatic waves.
abstract: The stochastic threshold for the heating of ions in a magnetized plasma with two electrostatic waves is experimentally characterized. Two obliquely propagating electrostatic modes are launched in a magnetized plasma with frequencies that differ by the ion cyclotron frequency. The values of the wave amplitudes where a rapid increase in the local ion temperature occurs is then parametrically investigated. It is found that the two threshold wave amplitudes are linearly related and that this dependence translates to a lower required energy density for the onset of heating when compared to the case of a single electrostatic wave. Agreement also is demonstrated between the experimentally observed threshold for stochastic heating and an analytical prediction [B. Jorns and E. Y. Choueiri, Phys. Rev. E 87, 013107 (2013)] for this threshold.
authors.affiliation: Electric Propulsion and Plasma Dynamics Laboratory (EPPDyL), Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: B
authors.initials: B
authors.lastname: Jorns
authors.affiliation: Electric Propulsion and Plasma Dynamics Laboratory (EPPDyL), Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: E Y
authors.initials: EY
authors.lastname: Choueiri