Plasma Expansion into a Vacuum

Abstract

The expansion of a semi-infinite, uniform plasma into a vacuum is studied by computer simulation. The solution resembles an analytic similarity solution except for a discontinuous front that precedes the plasma at a velocity of about 3(kT /mi)1/2. Thus, previous speculation that the initial burst of ions would be accelerated to velocities comparable to that of the thermal velocity of the plasma electrons on the basis of a fluid model alone is found to be not valid.

Ion acceleration by superintense laser-plasma interaction

“…Most of general studies of plasma expansion and related ion acceleration developed both before and after TNSA experiments 10 as well as more specific models of TNSA 11 so far proposed in the literature can be considered as (2006). 10 General studies of plasma expansion in vacuum include Allen and Andrews (1970); Crow et al (1975); Denavit (1979); Dorozhkina and Semenov (1998); Gurevich et al (1966); Mora and Pellat (1979); Pearlman and Morse (1978); and Widner et al (1971). Early papers focused on modeling ion acceleration in laser-produced plasmas include Kishimoto et al (1983); Pearl-suitable simplifications of the previous equations, falling into one of the two above mentioned categories (or suitable combinations of them) and obtained adding further, physically motivated assumptions.…”

Implications for the electron distribution from the stationary hydrodynamic model of a one-dimensional plasma expansion into vacuum

“…At this point, we emphasize that the result (19) is equivalent to (13). The last step of the simplification is to evaluate the limit.…”

“…However, this approach remains still valid in the generalized sense of Fourier transforms on tempered distributions. This is important in the final step, where we simplify the result (13).…”

“…This can be done either using a hydrodynamic description (e.g., Refs. [13][14][15] or in a more general way by using a kinetic ansatz (e.g., Refs. [16][17][18].…”

Adaptive Kinetic-Fluid Models for Expanding Plasmas

“…Plasma expansion into vacuum has been studied in a large number of works since publications by Gurevich et al [15], due to high relevance to laboratory devices and applications as well as space science. Dense plasma expands into a vacuum due to thermal electron pressure; some ions can be accelerated to very high energies as a result of this process [16]. The electrons can be assumed to remain in equilibrium with the electric field since the expansion occurs on a time scale long compared with electron time scale [17].…”