等离子体物理
It is known that a nonlinear Schr\"odinger equation describes the self-modulation of a large amplitude circularly polarized wave in relativistic electron-positron plasmas in the weakly and strongly magnetized limits. Here, we show that such…
Zonal flows are known to diminish turbulent transport in magnetic fusion. Interstingly, there is an adiabatic invariant that implies the emergence of zonal flow. The paper shows that if this invariant is decreasing (due to some external…
Magnetic field generation in ultra-intense laser-solid interactions is studied over a range of laser intensities relevant to next-generation laser facilities ($a_0 = 50-500$) using 2D particle-in-cell simulations. It is found that fields on…
We present in this part II the effects of the magnetic field intensity on the properties of the plasma discharge and the underlying phenomena for different propellant's ion mass. The plasma setup represents a perpendicular configuration of…
We present, in this two-part article, an extensive study on the influence that the magnitudes of the applied electric (E) and magnetic (B) fields have on a collisionless plasma discharge of xenon, krypton, and argon in a 2D radial-azimuthal…
A new Doppler backscattering (DBS) system, consisting of Q-band and V-band, has been installed and achieved its first data on the MAST-U spherical tokamak. The Q-band and V-band have separate microwave source systems, but share the same…
Significant progress has been made in designing magnetic fields that provide excellent confinement of the guiding enter trajectories of alpha particles using quasisymmetry (QS). Given the reduction in this transport channel, we assess the…
In a recent Letter [T. Dornheim \textit{et al.}, Phys. Rev. Lett. \textbf{121}, 255001 (2018)], it was predicted on the basis of \textit{ab initio} quantum Monte Carlo simulations that, in a uniform electron gas, the peak $\omega_0$ of the…
Plasma-based positron acceleration is still an open question, as the most efficient regimes for electron acceleration (quasi-linear and blowout) are not directly applicable to positrons. Nevertheless, positron acceleration is a stepping…
In this study, the first-of-its-kind use of active learning (AL) framework in thermal spray is adapted to improve the prediction accuracy of the in-flight particle characteristics and uses Gaussian Process (GP) ML model as a surrogate that…
Plasma acceleration is considered a prospective technology for building a compact multi-TeV electron-positron collider in the future. The challenge of this endeavor is greater for positrons than for the electrons because usually the…
We propose a new mechanism for generating coherent subcycle optical pulse by directing a relativistic electron beam (REB) into a plasma with a density up-ramp. The subcycle pulse is coherently emitted by bubble-sheath electrons in…
The development of machine learning techniques enables us to construct surrogate models from data of direct numerical simulations, which has important implications for modeling complex physical systems. In this paper, based on the output…
We examine dissipation and energy conversion in weakly collisional plasma turbulence, employing in situ observations from the Magnetospheric Multiscale (MMS) mission and kinetic Particle-in-Cell (PIC) simulations of proton-electron plasma.…
The role of a runaway current in a post disruption plasma is investigated through numerical simulations in an asymmetric magnetic reconnection event. While the runaways do not alter the linear growth of the island, they lead to a rotation…
We investigate the motion of charged particles in a turbulent electrostatic potential using guiding-center theory. By increasing the Larmor radius, the dynamics exhibit close-to-ballistic transport properties. The transition from diffusive…
A deep neural network is developed and trained on magnetic measurements (input) and EFIT poloidal magnetic flux (output) on the EAST tokamak. In optimizing the network architecture, we use automatic optimization in searching for the best…
Effects of resonant magnetic perturbations (RMPs) on tangential neutral beam heating in the EAST tokamak are studied numerically. RMPs with linear resistive magnetohydrodynamics response are used in the modeling. A variety of representing…
We present calculations of electrical resistivity for expanded boron, aluminum, titanium and copper plasmas using the Ziman formulation in the framework of the average-atom model. Our results are compared to experimental data, as well as…
Plasma-based CO2 conversion is a promising pathway towards greenhouse gas recycling. In the corresponding research field, various types of plasma reactors are applied for carbon dioxide dissociation. So far, spatial inhomogeneities of the…