Comments on the Paper “Fundamental Scaling of Adiabatic Compression of Field Reversed Configuration Thermonuclear Fusion Plasmas”

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The second law of thermodynamics is often expressed as the fact that the entropy of an isolated system increases when a spontaneous change takes place. While this statement is true, a more general formulation can easily be presented to students. Starting from the Kelvin formulation of the second law, one can show that the entropy of a closed adiabatic system increases when an irreversible (spontaneous) process occurs. As a consequence, equilibrium is reached when the entropy of such a system has reached its

Compact optimized stellarators offer novel solutions for confining high-beta plasmas and developing magnetic confinement fusion. The three-dimensional plasma shape can be designed to enhance the magnetohydrodynamic (MHD) stability without feedback or nearby conducting structures and provide drift-orbit confinement similar to tokamaks. These configurations offer the possibility of combining the steady-state low-recirculating power, external control, and disruption resilience of previous stellarators with the

The development of high power CW gyrotrons for ECRH heating of fusion relevant plasmas has been in progress for several years in a joint collaboration between different European research institutes and an industrial partner. Two development are on going, aiming, respectively, towards a 0.51-MW-210-s gyrotron at 118 GHz for the tokamaks TCV of CRPP (2 s pulse length) and Tore Supra of CEA (210 s pulse length), and towards a 1 MW-CW gyrotron at 140 GHz for the stellarator W7-X under construction in Greifswald

Zirconium is employed as the 'inert' component in several different inert matrix fuel concepts currently under development (cermet, oxide solution, etc.). Relative to the situation in standard light water reactors, this implies a very significant increase in the zirconium inventory, with a correspondingly enhanced importance of the nuclear data for zirconium in calculating safety related parameters. The present paper discusses new numerical results for various reactivity effects. On the basis of the current

As part of PSI's validatory efforts for neutronics calculations pertaining to inert matrix fuel (IMF) deployment in light water reactors, first-of-their-kind integral measurements have been carried out at the PROTEUS facility employing a specially fabricated Pu-Er-Zr IMF rod in a heterogeneous (boiling water reactor) test lattice. Analogous experiments have also been conducted with MOX and 'dummy' IMF rods, providing the basis for a systematic comparison of experimental and calculational results.

A characterization of the H-mode in Tokamak de Varennes (TdeV) is presented, combining results obtained from spectroscopic measurements with observations of global plasma parameters. Controlled L- and H-modes are obtained by applying an external bias on the divertor plate and/or by varying the plasma triangularity using similar steady-state discharges with electron cyclotron resonance heating (ECRH). A qualitative study of the impurity emission asymmetries is presented and discussed by proposing a simple mo

The prediction of the thermal energy confinement time, tau(th), for ITER size experiments is based on power law scalings obtained using data sets of present tokamak results in specific regimes, the most relevant being the ELMy H mode regime. A thorough statistical approach has provided a bust fit to these data with an estimation of the error bars which forms the basis for the ITER EDA design parameters. In this article the range of variation of the main parameters in the database are studied individually an

Fast particle driven instabilities are investigated at low toroidal field B-0 approximate to 1 T in tritium, deuterium and hydrogen plasmas. Tritium, deuterium and hydrogen neutral beams with energies of 160, 140 and 110 keV were injected, respectively, into tritium, deuterium and hydrogen plasmas. The destabilization of Alfven eigenmodes was observed during injection of tritium beams into a tritium plasma and during the injection of deuterium beams into a deuterium plasma but not during the injection of hy

Within the range of plasma shapes and plasma currents investigated, the electron confinement time, tau_Ee, increases with safety factor, density and negative triangularity similar to the Ohmic heating case. There is little dependence of tau_Ee on the heating location provided power deposition occurs inside the q=1 surface; as power deposition moves out of the inversion surface, tau_Ee decreases. The power-induced energy confinement degradation exponent (tau_Ee~PaP) is as usual: alpha_P ~-0.5. As a general t

Within the range of plasma shapes and plasma currents investigated, the electron confinement time, Tau_E increases with density, elongation and negative triangularity (-0.4

A new finite element (FE) scheme, based on the decomposition of a second order differential equation into a set of first order symplectic (Hamiltonian) equations, is presented and tested on a one-dimensional, driven Sturm-Liouville problem. Error analysis shows improved cubic convergence in the energy norm for piecewise linear ''tent'' elements, as compared to quadratic convergence for the standard and symplectic hybrid (i.e. 'tent' and piecewise constant) FE methods. The convergence deteriorates in the pre

The D-D fusion reactivity from JET plasmas has been optimized by using combined neutral beam injection and radiofrequency heating. Reaction rates of up to 2.9 x 10(16) reactions per second (equivalent to neutron emission rates of 1.45 x 10(16) neutrons per second) have been achieved. The best results were obtained in the double-null magnetic configuration or with plasmas limited by the inner wall. By far the largest fraction of the neutron production originates from beam induced reactions, although, in some

Comments on the Paper “Fundamental Scaling of Adiabatic Compression of Field Reversed Configuration Thermonuclear Fusion Plasmas”

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The second law: statement and applications

Physics of the compact advanced stellarator NCSX

European high-power CW gyrotron development for ECRH systems

Importance of zirconium cross sections in calculating reactivity effects for inert matrix fuels

Integral measurements with a plutonium inert matrix fuel rod in a heterogeneous light water reactor lattice

Characterization of impurities in L- and H-modes created by divertor biasing and plasma triangularity in TdeV

Considerations on energy confinement time scalings using present tokamak databases and prediction for ITER size experiments

Beam driven Alfven eigenmodes and fishbones in JET

EFFECT OF LOCALISED ELECTRON CYCLOTRON HEATING ON ENERGY CONFINEMENT AND MHD IN TCV

Preliminary Confinement Studies during ECRH in TCV

Symplectic finite element scheme: Application to a driven problem with a regular singularity

Studies of D-D Fusion Reactivity in High-Temperature Jet Plasmas