Transport simulation of negative magnetic shear discharges

Technical Report · Sat Oct 01 04:00:00 EDT 1994

DOI:https://doi.org/10.2172/10104519· OSTI ID:10104519

John, H; Taylor, T S; Lin-Liu, Y R; Turnbull, A D

In the present work the authors present simulations which show that the hollow current profile can be maintained in quasi-steady state through a self-consistently determined combination of bootstrap current and neutral beam and rf current drive. Controllability of the q profile is demonstrated by eliminating low m/n mode number instabilities from these discharges by maintaining q > 1.5 at all times, starting from appropriate initial conditions. At moderately high {beta}{sub p}, the bootstrap current can be a substantial fraction of the total current and the ability to maintain the proper total current density profile depends on the bootstrap current profile and the availability of suitable localized heating and current drive. In these simulations, they use electron cyclotron heating, ion cyclotron heating, and electron cyclotron and fast wave current drive. The ability to maintain the profiles is demonstrated using several energy transport models. Self-consistent transport simulations are used to model the SSC discharges using the ONETWO transport code coupled to rf heating and current drive packages FASTWAVE and TORAY. To accurately model inductive and driven current profile evolution, the additional source terms that arise in Faraday`s law due to internal flux surface motion are included by coupling the transport calculations to a fixed boundary equilibrium code. To test the sensitivity of the results to the transport model used, they model DIII-D discharges using thermal conductivities consistent with improved confinement DIII-D discharges, and with the Rebut-Lallia-Watkins model of energy transport.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-89ER51114
• OSTI ID: 10104519
• Report Number(s): GA-A--21847; IAEA-CN--60/D-D-II-8; CONF-940933--20; ON: DE95003941; BR: 35AT10020/35AT15040
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700330
BETA RATIO
CHARGED-PARTICLE TRANSPORT
DOUBLET-3 DEVICE
ELECTRON DENSITY
ENERGY TRANSFER
MAGNETIC SURFACES
PERFORMANCE
PLASMA CONFINEMENT
PLASMA KINETICS, TRANSPORT, AND IMPURITIES
PLASMA SIMULATION
THEORETICAL DATA
THERMAL CONDUCTIVITY
THERMONUCLEAR POWER PLANTS