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The distance between the last closed flux surface (LCFS) and the nearest electromagnetic coils is a dominating factor in the cost, size, and engineering difficulty of stellarators. The smallest magnetic gradient scale length on the LCFS -…
Observations of gamma-ray burst afterglows suggest that the correlation length of magnetic field fluctuations downstream of relativistic non-magnetized collisionless shocks grows with distance from the shock to scales much larger than the…
The onset and evolution of magnetic fields in laboratory and astrophysical plasmas is determined by several mechanisms, including instabilities, dynamo effects and ultra-high energy particle flows through gas, plasma and interstellar-media.…
We conduct a multiparametric study of driven magnetic reconnection relevant to recent experiments on colliding magnetized laser produced plasmas using particle-in-cell simulations. Varying the background plasma density, plasma resistivity,…
Stellarator fusion devices confine plasma by means of complex, non-planar electromagnetic coils. Understanding how the shape of the plasma boundary determines the required complexity of the coil set is a central open question in stellarator…
Molecular dynamics simulations are used to show that strong magnetization significantly increases the space and time scales associated with interparticle correlations. The physical mechanism responsible is a channeling effect whereby…
The design of any large stellarator requires a plan for the removal of the particles and heat that are exhausted across the plasma edge. This is called the divertor problem, for the particle exhaust must be diverted into pumping chambers.…
The electron beam propagation in a plasma medium is susceptible to several instabilities. In the relativistic regime typically the weibel instability leading to the current separation dominates. The linear instability analysis is carried…
The ability to separate large volumes of mixed species based on atomic mass appears desirable for a variety of emerging applications with high societal impact. One possibility to meet this objective consists in leveraging mass differential…
The magnetic field that supports tokamak and stellarator plasmas must be produced by coils well separated from the plasma. However the larger the separation, the more difficult it is to produce a given magnetic field in the plasma region,…
In magnetic confinement fusion devices, the equilibrium configuration of a plasma is determined by the balance between the hydrostatic pressure in the fluid and the magnetic forces generated by an array of external coils and the plasma…
We carry out 3D and 2D PIC-simulations of the expansion of a magnetized plasma that initially uniformly fills a half-space and contains a semi-cylindrical region of heated electrons elongated along the surface of the plasma boundary. This…
Magnetic helicity, and more broadly magnetic field line topology, impose constraints on the plasma dynamics. Helically interlocked magnetic rings are in a non-trivial topological state. It is harder to bring them into a topologically…
Stellarators confine fusion plasmas using three-dimensional magnetic fields composed of nested toroidal magnetic surfaces. In generic stellarators, trapped particles can drift across these surfaces and degrade plasma confinement. Certain…
Hot plasma is highly conductive in the direction parallel to a magnetic field. This often means that the electrical potential will be nearly constant along any given field line. When this is the case, the cross-field voltage drops in…
We demonstrate by computer simulations, laser plasma experiments, and analytic theory that a hitherto unknown instability is excited in the beam plasma system with finite transverse size. This instability is responsible for the generation…
Access to the plasma chamber in a stellarator reactor is essential for maintenance and diagnostics. However, the complex geometry of stellarator coils, often characterized by their strong twisting, can severely limit the space available for…
The penetration of plasma clouds, or plasmoids, across abrupt magnetic barriers (of the scale less than a few ion gyro radii, using the plasmoid directed velocity) is studied. The insight gained earlier, from experimental and computer…
Additional physics beyond standard hydrodynamics is needed to fully model the intracluster medium (ICM); however, as we move to more sophisticated models, it is important to consider the role of magnetic fields and the way the fluid…
We investigate the competition of magnetic reconnections in self-generated and external magnetic fields in laser-produced plasmas. The temporal evolution of plasma structures measured with self-emission imaging shows the vertical expansions…