New class of self-similar solutions for vacuum plasma expansion admitting mono-energetic ion spectra

TL;DR

This paper introduces a new class of self-similar plasma expansion solutions that can produce quasi-monoenergetic ion spectra by controlling electron temperature with tailored laser pulses, supported by analytical modeling and PIC simulations.

Contribution

It presents a novel analytical model for plasma expansion into vacuum that achieves mono-energetic ion spectra through controlled electron temperature.

Findings

Analytical model predicts mono-energetic ion spectra with tailored laser profiles.

PIC simulations confirm the analytical predictions.

Controlled electron temperature leads to phase-space ion concentration.

Abstract

We report a new class of self-similar solutions for plasma expanding into vacuum that allows for quasi-monoenergetic ion spectra. A simple analytical model takes into account externally controlled time-dependent temperature of the hot electrons. When the laser temporal profile is tailored properly, the quasi-neutral self-similar expansion of the plasma results in ion concentration in the phase-space at a particular velocity thus producing a quasi-monoenergetic spectrum. We prove this analytical prediction using a 1D partice-in-cell (PIC) simulation where the time-dependent plasma temperature is controlled by two laser pulses shot at a foil at a suitable time delay.