Laser-Produced Magnetic-Rayleigh-Taylor Unstable Plasma Slabs in a 20 T Magnetic Field

Abstract

Magnetized laser-produced plasmas are central to many novel laboratory astrophysics and inertial confinement fusion studies, as well as in industrial applications. Here we provide the first complete description of the three-dimensional dynamics of a laser-driven plasma plume expanding in a 20 T transverse magnetic field. The plasma is collimated by the magnetic field into a slender, rapidly elongating slab, whose plasma-vacuum interface is unstable to the growth of the "classical", fluid-like magnetized Rayleigh-Taylor instability.The combination of high-power lasers with externally applied high-strength magnetic fields of up to kT [1,2] has been seminal in the development of many recent applications in laboratory astrophysics [3][4][5][6][7], in novel concepts in laser-[8-10] and magnetically-driven [11,12] inertial confinement fusion physics, and in industrial applications [13,14]. Beside understanding the dynamics of the plasma expansion across a magnetic field, of particular importance is to grasp the nature of rapidly growing instabilities which may develop and profoundly modify the morphology and characteristics of these plasmas. Indeed, the presence of striations and flutes have often been associated with the development of instabilities and in particular with the lower hybrid drift instability (LHDI) or one of its variants [15][16][17]. In addition, anomalous resitivity driven by the LHDI [18,19] can also affect the plasma microscopically, with potentially important consequences on magnetic field diffusion and the growth of other instabilities. Among those, the magnetic Rayleigh-Taylor instability (MRTI) [20,21] is known to play a key role on the dynamics of laboratory [22], as well as astrophysical plasmas [23,24]. So far however, it has not been isolated in laser-produced high energy density plasmas.A major parameter affecting the stability and dynamics of these plasmas is the relative direction of the applied magnetic field with respect to the plasma expansion axis. While for an aligned magnetic field the plasma is collimated into an axisymmetric, stable jet-like flow [4,5], for a transverse magnetic field both stable[25] and unstable flows [26] were observed and a clear understanding of the plasma evolution is still missing.Here, we provide the first complete description of the three-dimensional dynamics of a laser-driven plasma plume in a transverse 20 T magnetic field. We show that the plasma is collimated into a slender, rapidly expanding slab, and demonstrate that under these conditions, the growth of flute-like, interchange modes at the plasma-vacuum interface that extend in the form of spikes into the vacuum is due to the classical, fluid-like, magnetic Rayleigh-Taylor instability (MRTI). Interestingly, we find that to recover quantitatively in the simulations the penetration of these spikes into the vacuum, a subgrid-scale model of anomalous resistivity needs to be included. This anomalous resistivity could be induced by the micro-turbulence generated by the LHDI, which for our plasma condition...

Scalings of Rayleigh-Taylor Instability at Large Viscosity Contrasts in Porous Media

“…Rayleigh-Taylor (RT) instability is a buoyancy-driven instability developing when a denser fluid is accelerated against a less dense fluid. It favors mixing between the two fluids and is genuinely observed in inertial confinement fusion [1][2][3], plasmas [4], liquid films [5], material deformation [6], oceanography [7], and astrophysics [8,9], to name a few. Motivated by the interest to control this mixing, universal scalings, quantifying the interpenetration of the two fluids as a function of the acceleration or the density and viscosity differences across the interface, are of tantamount importance.…”

Inferring possible magnetic field strength of accreting inflows in EXor-type objects from scaled laboratory experiments

“…Hence, we simulate a central line of the expanding plasma with ESTHER. The simulation does not treat the background magnetic field; the justification for this is that within its expansion, as it propagates the plasma expels the magnetic field (Khiar et al 2019). This code solves, according to a Lagrangian scheme, the fluid equations for the conservation of mass, momentum, and energy.…”

“…1 indicates the situation modelled in this article. We note that such a configuration has already been investigated in a number of earlier studies performed using various plasma machines (Sucov et al 1967;Bruneteau et al 1970;Plechaty et al 2013;Tang et al 2018;Khiar et al 2019). In this work, we prolong these previous efforts by generating plasmas that are scaled to the parameters of the massive accretion events which are our focus, as detailed below and in Table 1.…”

A numerical study of gravity-driven instability in strongly coupled dusty plasma. Part 1. Rayleigh–Taylor instability and buoyancy-driven instability

“…2014; Khiar et al. 2019; Garai, Ghose-Choudhury & Guha 2020). This instability has been observed in diverse situations such as a supernova explosion (Norman et al.…”

“…Furthermore, in the context of plasma medium, the charged species respond to electromagnetic forces, and various scenarios arise where an inverse stratification against a force (and/or a pseudo force due to the choice of the frame) leads to this instability (Hoshoudy 2009;Liberatore et al 2009). Studies for different types of plasmas under various conditions have been carried out (Dickinson et al 1962;Ariel & Bhatia 1970;Nayyar & Trehan 1970;Takabe et al 1985;Mikhailenko, Mikhailenko & Weiland 2002;Ma et al 2006;Sen, Fukuyama & Honary 2010;Haines et al 2014;Hoshoudy 2014;Kessler, Dahlburg & Ganguli 2014;Weber et al 2014;Khiar et al 2019;Garai, Ghose-Choudhury & Guha 2020). This instability has been observed in diverse situations such as a supernova explosion (Norman et al 1981;Arnett et al 1989), geophysics (Plag & Jüttner 1995), astrophysics (Allen & Hughes 1984;Zingale et al 2005), atmospheric physics (Keskinen et al 1981), liquid atomization (Beale & Reitz 1999;Kong, Senecal & Reitz 1999), fusion physics (Chertkov 2003;Kadau et al 2004;Hoshoudy 2011;Srinivasan & Tang 2013), oceanography (Debnath 1994), turbulent mixing (Abarzhi 2010(Abarzhi , 2008Abarzhi & Rosner 2010), etc.…”