skip to main content

Title: Ignition threshold for non-Maxwellian plasmas

An optically thin p-{sup 11}B plasma loses more energy to bremsstrahlung than it gains from fusion reactions, unless the ion temperature can be elevated above the electron temperature. In thermal plasmas, the temperature differences required are possible in small Coulomb logarithm regimes, characterized by high density and low temperature. Ignition could be reached more easily if the fusion reactivity can be improved with nonthermal ion distributions. To establish an upper bound for the potential utility of a nonthermal distribution, we consider a monoenergetic beam with particle energy selected to maximize the beam-thermal reactivity. Comparing deuterium-tritium (DT) and p-{sup 11}B, the minimum Lawson criteria and minimum ρR required for inertial confinement fusion (ICF) volume ignition are calculated with and without the nonthermal feature. It turns out that channeling fusion alpha energy to maintain such a beam facilitates ignition at lower densities and ρR, improves reactivity at constant pressure, and could be used to remove helium ash. On the other hand, the reactivity gains that could be realized in DT plasmas are significant, the excess electron density in p-{sup 11}B plasmas increases the recirculated power cost to maintain a nonthermal feature and thereby constrains its utility to ash removal.
Authors:
 [1] ;  [1] ;  [2]
  1. Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
22489831
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 11; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ASHES; BEAMS; BORON 11; BREMSSTRAHLUNG; D-T OPERATION; ELECTRIC UTILITIES; ELECTRON DENSITY; ELECTRON TEMPERATURE; HEAVY ION FUSION REACTIONS; HELIUM ASH; INERTIAL CONFINEMENT; LAWSON CRITERION; PLASMA; REACTIVITY; TEMPERATURE RANGE 0065-0273 K; THERMONUCLEAR IGNITION; THERMONUCLEAR REACTIONS