Dense plasma heating by crossing relativistic electron beams

Abstract

Here we investigate, using relativistic fluid theory and Vlasov-Maxwell simulations, the local heating of a dense plasma by two crossing electron beams. Heating occurs as an instability of the electron beams drives Langmuir waves, which couple nonlinearly into damped ion-acoustic waves. Simulations show a factor 2.8 increase in electron kinetic energy with a coupling efficiency of 18%. Our results support applications to the production of warm dense matter and as a driver for inertial fusion plasmas.

Preparations for a European R&D roadmap for an inertial fusion demo reactor

“…Firstly, it is possible to aim laser-formed channels precisely and mitigate both the hosing and filamentation instabilities [37]. Secondly, although the growth rate for the instability that seeds energy into the Langmuir wave is maximal for the case of orthogonal electron beams, Ratan et al [45] demonstrated that Langmuir waves are seeded over the full range of intersection angles including the least optimal case of counter-propagating beams. This implies that the auxiliary heating mechanism should be robust against timing jitters between laser beams that makes this scheme experimentally viable for testing on facilities such as NIF and LMJ.…”

“…We discuss here a potential solution to the two major roadblocks on the path to the realization of inertial fusion: insufficient energy in the central hot spot, and the susceptibility of high-convergence ratio implosions to hydrodynamic instabilities and drive asymmetries. Previous work has established that it is possible, in principle, for energy to be deposited into a high-density plasma via collisionless interactions at the intersection of two crossing relativistic electron beams with the maximum efficiency of deposition occurring for the case of orthogonal beams [44,45]. Crucially, unlike the collisional heating mechanisms used in fast ignition schemes, the collisionless nature of the interaction means that this auxiliary heating scheme does not disrupt the isobaric nature of a central hot-spot implosion and allows for targeted energy deposition in the hot spot rather than the surrounding dense fuel.…”

Observation of a high degree of stopping for laser-accelerated intense proton beams in dense ionized matter

“…In the fast ignition scheme [6][7][8][9] , a short and intense pulse of energetic charged particles-electrons, protons, or heavy ions-generated by an ultra-high-intensity laser, is directed toward the pre-compressed fusion pellet. The charged-particle beam requirements to achieve ignition have been discussed and studied in detail previously [10][11][12][13][14] based on single-particle stopping theory. However, the collective effects induced by high-current charged-particle beams could alter significantly the projected range, the magnitude of energy deposition, and therefore change the requirements for ignition correspondingly.…”

Enhancement of Electron Temperature under Dense Homogenous Plasma by Pulsed Laser Beam

“…The electron temperature is an important parameter in determining the classification of the plasma (thermal and non thermal) by comparing its values with the temperature of the ions inside the plasma. Therefore, the researchers focused on this parameter in order to change the values of electron temperature according to the requirements of practical applications such as including nuclear fusion, plating operations and in industrial applications (1,2,3).There are several methods for heating plasma and varying the electron temperature values such as, applying a magnetic field or interacting by a laser beam with plasma (4,5,6,7).The process of energy absorbing of the laser beam occurs by inverse bremsstrahlung (IB). The (IB) process refers to absorb the energy of the photons by plasma electrons and gaining energy leads to heating the plasma and raising the temperature of the electrons.…”