Runaway modeling in ORMAK and TNS

Technical Report · Fri Jul 01 00:00:00 EDT 1977

DOI:https://doi.org/10.2172/7315993· OSTI ID:7315993

Cooper, A.; Swain, D. W.; Marcus, F. B.; Kammash, T.

A zero-dimensional tokamak start-up code is used to investigate the generation of runaway electrons in the Oak Ridge Tokamak (ORMAK) and The Next Step (TNS) and the effect of the runaways on the plasma breakdown, current, and energy balance, The runaways, which are considered collisionless, are treated self-consistently in the circuit equation by including a runaway current component (determined from a runaway rate equation). During the earliest stages of a discharge, the total current in the plasma is so low that closed flux surfaces do not exist. Runaways produced are lost almost instantly because they follow magnetic field lines that intersect the limiter. Once the current in the tokamak builds up sufficiently, closed flux surfaces start forming which improves runaway containment. The time tau when this occurs is uncertain. Results on ORMAK and TNS are displayed for different values of tau (before which any runaway created is assumed to be lost instantaneously). The assumption of flux surface closure after some arbitrary time tau is then justified by modeling an ORMAK discharge which includes the effects on runaway confinement of error fields generated by currents flowing in the leads to the toroidal field coils. Also shown are ORMAK simulations in different density regimes and TNS results for different loop voltage pulses.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: US Energy Research and Development Administration (ERDA)
• DOE Contract Number: W-7405-ENG-27
• OSTI ID: 7315993
• Report Number(s): ORNL/TM-5905; TRN: 77-017043
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ORMAK DEVICES
RUNAWAY ELECTRONS
MATHEMATICAL MODELS
TOKAMAK TYPE REACTORS
COMPUTER CALCULATIONS
MAGNETIC FIELD CONFIGURATIONS
CLOSED PLASMA DEVICES
ELECTRONS
ELEMENTARY PARTICLES
FERMIONS
LEPTONS
THERMONUCLEAR DEVICES
THERMONUCLEAR REACTORS
TOKAMAK DEVICES
700105* - Fusion Energy- Plasma Research- Plasma Kinetics-Theoretical- (-1987)