LAUSR

The self-channeling of a high power (≤500 MW) sub-nanosecond microwave beam in the plasma formed by a neutral gas (>103 Pa) ionization was demonstrated by Shafir et al. [Phys. Rev. Lett. 120, 135003 (2018)]. In the present research, this effect is observed and studied in detail in a plasma, preliminarily formed by an rf discharge, in a low ( 103 Pa) ionization was demonstrated by Shafir et al. [Phys. Rev. Lett. 120, 135003 (2018)]. In the present research, this effect is observed and studied in detail in a plasma, preliminarily formed by an rf discharge, in a low (<150 Pa) pressure gas. The results of analytical modeling and numerical particle-in-cell simulations show that ionization-induced channeling can be realized at a significantly lower power of the microwave beam and gas pressure if the preliminarily formed plasma is radially non-uniform with minimal on axis density.