Abstract The present concepts for power and particle control in the next generation of tokamak experiments rely upon atomic processes to transfer the power and momentum from the divertor plasma to the divertor chamber walls. These concepts are being evaluated with sophisticated one‐ and two‐dimensional divertor models. We present a survey of some of the candidate atomic processes of impurity radiation, hydrogen radiation and atomic physics and molecular effects to aid the development of the models.

10.1002/ctpp.2150340232

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Citations (17)

Calculations of impurity radiation and its effects on tokamak experiments

Nuclear Fusion (1977)

Roderick V. Jensen D.E. Post W.H. Grasberger C. Bruce Tarter W.A. Lokke

The impurity radiation for typical tokamak parameters has been numerically calculated using an "average-ion model". Coronal equilibrium values for the emission of oxygen, iron, molybdenum, tungsten and gold were determined from the steady-state solutions of a set of related rate equations which included the effects of electron collisional ionization and excitation, dielectronic and radiative recombination, Δn = 0 and Δn ≠ 0 line transitions, and bremsstrahlung. The results for oxygen, iron, and molybdenum compare very well with other calculations. Since impurities diffusing in a tokamak are not expected to be in coronal equilibrium, time-dependent radiation calculations were also performed. A comparison of these non-equilibrium loss rates with those calculated under the assumption of coronal equilibrium indicates that coronal radiation calculations do not significantly underestimate the moderate- and high-Z impurity radiation losses for neoclassical diffusion velocities in large tokamaks, such as Princeton Large Torus and Tokamak Fusion Test Reactor. Finally, the detailed steady-state emission rates were used to investigate the effects of various concentrations of impurities on the neτ requirements for breakeven, ignition, and Q = 5 beam-driven reactor experiments.

10.1088/0029-5515/17/6/007

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Citations (180)

Possible neutral beam requirements for TFTR upgrades

B. Prichard R. Little D.E. Post J. Schmidt

A discussion is provided of possible neutral beam requirements and constraints for a TFTR upgrade. The time scale is the early 80s and beams of 250 keV D/sup 0/, probably using 65 ampere negative ion sources, existing power supplies and vacuum enclosures would be required. (MHR)

Upgrade

Ampere

Source

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Alpha-particle simulation and diagnostics using /sub 3/He/sup + +/ minority ICRF heating

D.E. Post D.Q. Hwang D. R. Mikkelsen F. Seidl

We have investigated the theoretical feasibility of using fast /sub 3/He/sup + +/ ions, produced by ICRF minority heating, to simulate the behavior of fusion-produced /sub 4/He/sup + +/ ions in large fusion experiments. This proposed technique would allow the study of alpha-particle-like heating in near-term experiments, such as TFTR, JET, and JT-60, without the necessity of high levels of neutron production and the subsequent activation. The results of our calculations study show that ICRF minority heating should be able to produce confined fast /sub 3/He/sup + +/ distributions in TFTR-sized experiments with an energy distribution and density similar to those expected for fast alpha particles in fusion-reactor experiments, such as INTOR/FED/NET.

Alpha particle

Fusion power

Particle (ecology)

Source

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Cool, High-Density Regime for Poloidal Divertors

Physical Review Letters (1982)

M. Petravić D.E. Post D. Heifetz J. Schmidt

Calculations have been performed which demonstrate the possibility of operating poloidal divertors at high densities and low temperatures. Ionization of recycling neutral gas near the divertor neutralizer plate amplifies the input particle flux thereby raising the plasma density and lowering the plasma temperature. Low-temperature, high-density operation should reduce the erosion rate of the divertor walls and plate, and ease the pumping requirements in future large tokamaks.

10.1103/physrevlett.48.326

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Citations (113)

Collision Processes of He2+

Springer eBooks (1987)

R. K. Janev W. D. Langer D.E. Post K. Evans

10.1007/978-3-642-71935-6_6

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An analytic one-dimensional divertor model with neutral sources

Journal of Nuclear Materials (1984)

D.E. Post W. D. Langer M. Petravić

Dimensionless quantity

Fusion power

10.1016/0022-3115(84)90119-3

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Citations (33)

ITER: Physics basis

D.E. Post

Summary form only given. The physics studies for ITER (International Experimental Thermonuclear Reactor) will begin with experiments in hydrogen to address questions of confinement, operational limits, divertor performance, disruption behavior, heating, and current drive efficiency. Experiments with D and ³ He will be done to test the RF heating systems, simulate alpha particle effects, and further address the same issues raised during hydrogen operation, and to test the diagnostic systems expected to be used during D/T operation. D or ³ He operation will provide moderate levels of activation so that access will be limited. Experiments will then proceed with D/T. Experiments at progressively higher levels of Q will be performed, until ignited operation is obtained. The goal is to study long-pulse (⩾200-s) ignited plasmas with inductive operation. In addition, the plasma and divertor performance with progressively higher levels of current drive will be studied. The goal during the final portion of physics studies will be to identify a long-pulse (1000 s to steady state) mode of plasma operation which can be run reliably during the technology phase to produce a fusion power of ~1000 MW or more with a minimum of disruptions

Thermonuclear Fusion

10.1109/plasma.1990.110570

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Citations (11)