Stable relativistic/charge-displacement channels in ultrahigh power density (≈10²¹ W/cm³) plasmas

Abstract

Robust stability is a chief characteristic of relativistic/charge-displacement self-channeling. Theoretical analysis of the dynamics of this stability (i) reveals a leading role for the eigenmodes in the development of stable channels, (ii) suggests a technique using a simple longitudinal gradient in the electron density to extend the zone of stability into the high electron density/high power density regime, (iii) indicates that a situation approaching unconditional stability can be achieved, (iv) demonstrates the efficacy of the stable dynamics in trapping severely perturbed beams in single uniform channels, and (v) predicts that ≈10⁴ critical powers can be trapped in a single stable channel. The scaling of the maximum power density with the propagating wavelength λ is shown to be proportional to λ⁻⁴ for a given propagating power and a fixed ratio of the electron plasma density to the critical plasma density. An estimate of the maximum power density that can be achieved in these channels with a power of ≈2 TW at a UV (248 nm) wavelength gives a value of ≈10²¹ W/cm³ with a corresponding atomic specific magnitude of ≈60 W/atom. The characteristic intensity propagating in the channel under these conditions exceeds 10²¹ W/cm².