Plasma Physics
Understanding the partitioning of turbulent energy between ions and electrons in weakly collisional plasmas is crucial for the accurate interpretation of observations and modelling of various astrophysical phenomena. Many such plasmas are…
In this work we consider the problem of optimizing a stellarator subject to hard constraints on the design variables and physics properties of the equilibrium. We survey current numerical methods for handling these constraints, and…
Transit-time damping (TTD) is a process in which the magnetic mirror force -- induced by the parallel gradient of magnetic field strength -- interacts with resonant plasma particles in a time-varying magnetic field, leading to the…
Prompted by the relevant problem of temperature inversion (i.e. gradient of density anti-correlated to the gradient of temperature) in astrophysics, we introduce a novel method to model a gravitationally confined multi-component…
We perform experiments in the Large Plasma Device (LAPD) at the University of California, Los Angeles, studying how different end-electrode biasing schemes modify the radial potential profile in the machine. We impose biasing profiles of…
Polarized electron beam production via laser wakefield acceleration in pre-polarized plasma is investigated by particle-in-cell simulations. The evolution of the electron beam polarization is studied based on the…
We report the first high-repetition rate generation and simultaneous characterization of nanosecond-scale return currents of kA-magnitude issued by the polarization of a target irradiated with a PW-class high-repetition-rate Ti:Sa laser…
First of a kind 6D-Vlasov computer simulations of high frequency ion Bernstein wave turbulence for parameters relevant to the tokamak edge show transport comparable to sub-Larmor-frequency gyrokinetic turbulence. The customary restriction…
Self-focusing and guiding of ultra-short (pulse duration: L<lambda_P: plasma wavelength), intense laser pulses in underdense plasma relevant to laser wakefield electron acceleration has been studied numerically. The analysis considers…
The Bernstein wave is a well-known electrostatic eigen-mode in magnetized plasmas, and it is of broad connection to multiple disciplines, such as controlled nuclear fusions and astrophysics. In this work, we extend the Bernstein mode from…
In laser-driven indirect inertial confinement fusion (ICF), a hohlraum--a cavity constructed from high-Z materials--serves the purpose of converting laser energy into thermal x-ray energy. This process involves the interaction of…
We propose a method for reconstructing the fluctuation components of the electron velocity distribution function f(v_perp), and the electron entropy, which is a functional of f(v_perp) expressed as -f(v_perp)lnf(v_perp)dv_perp, using the…
A new sightline geometry for the fast-ion D-alpha (FIDA) diagnostic on the Large Helical Device (LHD) has been confirmed to measure signals for high-energy fast ions produced by negative-ion neutral beam injection. The newly installed…
This paper explores 4 different magnetic field topologies for application to spherical inertial confinement fusion implosions: axial, mirror, cusp and closed field lines. A mirror field is found to enhance the impact of magnetization over…
This paper contributes in the first part to the correct understanding of the linear limit in the Schamel equation (S-equation) from the perspective of structure formation in collisionless plasmas. The corresponding modes near equilibrium…
While hydroxyl radicals ($\cdot$OH) play an important role as potent oxidizing agents in various plasma applications, their high reactivity confines them to a thin layer at the plasma-liquid interface, posing challenges in comprehending the…
A major challenge in nuclear fusion research is the coherent combination of data from heterogeneous diagnostics and modelling codes for machine control and safety as well as physics studies. Measured data from different diagnostics often…
This paper presents the first gyrokinetic (GK) simulations of edge and scrape-off layer (SOL) turbulence accelerated by a velocity-space spectral approach in the full-f GK code GENE-X. Building upon the original grid velocity-space…
Mechanism of generating collisionless shock in magnetized gas plasma driven by laser-ablated target plasma is investigated by using one-dimensional full particle-in-cell simulation. The effect of finite injection time of target plasma,…
Injection process of pickup ion acceleration at a heliospheric termination shock is investigated. Using two-dimensional fully kinetic particle-in-cell simulation, accelerated pickup ions are self-consistently reproduced by tracking long…