The dependencies of energy confinement on the main engineering parameters have been investigated in the Mega Ampere Spherical Tokamak (MAST) in H-mode by expanding operational space towards higher plasma currents (up to 1.2MA) and heating powers (up to 3.5MW). Multivariate fits show that the dependence of energy confinement time on plasma current Ip is weaker than linear while the dependence on...

A ‘‘rotating wall’’ perturbation technique enables confinement of up to 3310 electrons or 10 ions in Penning–Malmberg traps for periods of weeks. These rotating wall electric fields transfer torque to the particles by exciting Trivelpiece–Gould plasma modes with kzÞ0 and mu51 or 2. Modes that rotate faster than the plasma column provide a positive torque that counteracts the background drags, r...

Following a 7.5-h transport haul, juvenile pallid sturgeon (Scaphirhynchus albus) showed a small but significant increase in plasma cortisol to 4.7 ng ml but similar increases did not occur after fish were handled in a net held in the air for 30 s. Subsequent experiments on yearling pallid sturgeon and hybrid pallid×shovelnose (S. albus×platorynchus) sturgeon using the same 30-s handling stress...

This report surveys mathematical results related to plasma turbulence obtained while supported by the VSGC Graduate Research Fellowship. The solar-wind and interstellar medium are highly turbulent plasmas exhibiting certain features ubiquitous across present numerical and phenomenological theories. The objective of the present research is to provide a rigorous validation of such aspects of thes...

Four quasi-axisymmetric compact stellarator plasma and coil configurations are analyzed for their potential as reactors. A 0-D (volume-average) approach for optimizing the main reactor parameters allows study of the relationship between global parameters and the compatibility of different constraints for a given power output including plasma-coil spacing, coil-coil spacing, maximum field and co...

Two types of instabilities were previously identified in inductive discharges having an expanding chamber when negative ions are present: i the source instability, occurring in the neighborhood of the capacitive-to-inductive E to H transition, and ii the downstream instability, which was shown to be the periodic formation and propagation of double layers. These unstable double layers were found...

It is shown that the thermodynamic maximum-entropy principle predicts negative specific heat for a stationary, magnetically self-confined current-carrying plasma torus. Implications for the magnetic self-confinement of fusion plasma are considered.

The long-term interest in nuclear fusion using tokamaks has yielded many published reactor designs. This study performs the first meta-analysis of tokamak reactor designs in an attempt to unveil new understanding not available in the traditional bottom-up method of looking at each design individually. Forty tokamak designs intended to produce significant fusion power at gains above one were ide...

The extreme shaping capabilities of the TCV tokamak have been used to investigate the effect of the plasma geometry on the confinement of non recycling trace impurities injected by means of the laser blow-off technique. The progression of the injected Silicon in the core of TCV Ohmic limiter plasmas was followed by the 200-channel soft x-ray photodiode array with good spatial and temporal resol...