Ion Acceleration in Strong Electromagnetic Interactions with Plasmas

Energetic ions of energy up to $7k{T}_e$ are detected when an inhomogeneous plasma ($\frac{T_e}{T_i}\cong 10$) is irradiated by microwave pulses ($\frac{{E_0}^2}{4\pi \mathrm{nk}{T}_e}\approx {10}^{-2\mathrm{}}$) of short durations ($\tau$ approximately twice the ion-plasma period). Time- and space-resolved analyses trace their origin to the generation of density cavitons by ponderomotive forces. The axially directed energetic-ion flux carries a significant fraction of incident electromagnetic energy.