Suprathermal electrons from the anti-Stokes Langmuir decay instability cascade

Feng, Qingsong; Aboushelbaya, Ramy; Mayr, M. W.; Spiers, Ben; Paddock, Robert W.; Ouatu, I.; Timmis, R.; Wang, R. H. W.; Cao, Lihua; Liu, Z. J.; Zheng, Chunyang; He, X. T.; Norreys, P.

doi:10.1103/physreve.105.045208

Cited by 5 publications

(4 citation statements)

References 53 publications

(89 reference statements)

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“…It can also be seen that SRBS bursts at points a and d, wave-breaking and other nonlinear effects play a vital role in this phenomenon. The maximum value of the EPW field can be obtained by Coffey's warm nonrelativistic wave breaking limit, where β = 3v 2 te /v 2 ϕ , and v te , ω pe are the electron thermal velocity and plasma frequency, respectively [39]. From equation ( 11), E max depends on the plasma density and electron temperature, and becomes lower when the density decreases.…”

Section: Electric-field Characteristics Of Srsmentioning

confidence: 99%

Suppression of stimulated Raman scattering in plasma by an ultra-wideband stochastic phase low-coherence laser

Zhou

Jiao

et al. 2023

Plasma Phys. Control. Fusion

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Suppression of the stimulated Raman scattering (SRS) by a stochastic phase low-coherence laser (SPLL) in homogeneous plasma is investigated by theoretical analysis and one-dimensional particle-in-cell (PIC) simulation. A simple model is established, in which the SPLL is modeled as a combination of a monochromatic laser and a broadband laser. When the phase randomness increases, the bandwidth of SPLL is broadened and the energy proportion of the monochromatic laser component is reduced. PIC simulation shows that SPLL can suppress SRS well and effectively control the number and energy of hot electrons. Various phenomena in the nonlinear process, such as the nonlinear frequency shift, the competition between forward-scattering and back-scattering modes, are explained in details.

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Section: Electric-field Characteristics Of Srsmentioning

confidence: 99%

Suppression of stimulated Raman scattering in plasma by an ultra-wideband stochastic phase low-coherence laser

Zhou

Jiao

et al. 2023

Plasma Phys. Control. Fusion

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“…It was found that the SRS rescattering can fill this phase velocity gap [23] and hot electrons can be produced through the interaction of a discrete spectrum of plasma waves generated from BSRS, FSRS, and rescattering. In addition, it was found that the LDI [24,25] and anti-Stokes LDI (ALDI) [26,27] following BSRS can heat electrons to higher energies because the EPW from the LDI has a slightly higher phase velocity. In order to provide overlapped trapping regions for different EPWs in their phase velocities, this cascade acceleration often imposes high demands on the electron density.…”

Section: Introductionmentioning

confidence: 99%

Anomalous hot electron generation via stimulated Raman scattering in plasma with up-ramp density profiles

Jiang,

Weng,

et al. 2024

Plasma Phys. Control. Fusion

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We investigate the evolution and propagation of the electron plasma waves (EPWs) excited by stimulated Raman scattering (SRS) in the inhomogeneous plasma theoretically and numerically with particle-in-cell (PIC) simulations. A theoretical model of EPWs in inhomogeneous plasmas is presented, which shows that the evolution of the EPW wavenumber is mainly related to the plasma density profile rather than the plasma electron temperature, in agreement with PIC simulations. When the density gradient is positive along the propagation direction of an EPW, its wavenumber decreases with time and consequently its phase velocity increases continuously, causing the trapped electrons to be accelerated to anomalous high energy. Furthermore, it is found that the Langmuir decay instability tends to reduce the levels of SRS saturation and electron acceleration and produce hot electrons in the opposite direction. This work provides a new understanding of electron heating due to SRS excitation.

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“…Two are currently the most actively pursued of many proposed routes to ICF: the indirect-drive approach [2], where the laser energy is first converted into x-rays that then go on to drive the compression of a spherical deuterium-tritium fuel capsule, and the direct drive scheme [3], where the laser beams irradiate and thereby compress, the fuel capsule directly. Both systems depend heavily on laser-plasma interactions (LPI) [4,5], which can degrade implosion output by lowering laser coupling to the target, increasing drive asymmetries, and preheating the fuel by producing and depositing suprathermal electrons. Cross-beam energy transfer (CBET), stimulated Brillouin scattering (SBS) [5][6][7][8], and stimulated Raman scattering (SRS) [9][10][11] are examples of laser plasma instabilities that prevent the development of the necessary time-dependent drivesymmetry in ICF.…”

Section: Introductionmentioning

confidence: 99%

Effect of chirp on stimulated-forward Raman scattering in a magnetised plasma with rippled density for fusion applications

2023

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Stimulated Raman scattering (SRS) is one of the mechanisms limiting power scalingin inertial confinement fusion (ICF). In this work, we demonstrate the effectivesuppression of SRS by the combined effects of static density fluctuations and anazimuthal magnetic field with a propagating chirped laser pulse. In the presence ofan azimuthal magnetic field, chirped laser pulse propagates through a density-rippledplasma and undergoes stimulated-forward Raman scattering (SFRS), resulting intwo radially localized electromagnetic sidebands waves and a lower-hybrid wave.Absolute and growing modes saturate due to ion density fluctuations, which thensuppress instability growth through mode coupling. The modes modified by thecombined effect of chirp and azimuthal magnetic field are effectively damped aftersaturation. As a result, the overall growth rate of the instability reduces. Thecomparison of positive and negative chirp demonstrated that when a positive chirp isbeing used, instability is more effectively suppressed. Based on non-local theory, wehave analyzed the growth of the SFRS for positive and negative chirp and estimatedit for ICF-relevant parameters and observed the effect of the growth rate.

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Suprathermal electrons from the anti-Stokes Langmuir decay instability cascade

Cited by 5 publications

References 53 publications

Suppression of stimulated Raman scattering in plasma by an ultra-wideband stochastic phase low-coherence laser

Suppression of stimulated Raman scattering in plasma by an ultra-wideband stochastic phase low-coherence laser

Anomalous hot electron generation via stimulated Raman scattering in plasma with up-ramp density profiles

Effect of chirp on stimulated-forward Raman scattering in a magnetised plasma with rippled density for fusion applications

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