Abstract Details

Presentation:submitted:by:
iccpresentation06.pdf2006-03-09 17:13:00Wendell Horton

Energy Confinement Scaling Predictions for the Kinetically Stabilized Tandem Mirror

Author: Wendell Horton
Submitted: 2005-12-20 10:56:13

Co-authors: J. Pratt

Contact Info:
University of Texas at Austin
1 University Station C1600
Austin, TX   78712
USA

Abstract Text:
We undertake a transport study for the kinetically stabilized tandem
mirror (KSTM), an attractive magnetic confinement device for achieving a steady-state burning plasma. For a MHD stable system, we investigate three different radial transport models with Bohm, gyro-Bohm, and electron temperature gradient (ETG) scaling. As a conservative estimate, numerical coefficients in the models are taken to be consistent with tokamak and stellarator databases. The plug mirrors create an ambipolar potential that controls end losses, whereas radial losses are driven by drift wave turbulence, which lowers the electron temperature through radial trapped particle modes and ETG transport losses. We analyze the
radial transport equations, taking into account the Pastukhov energy and particle end losses. For mirror ratio $R_m=9$ and a large density ratio between plug and central cell regions, we have a high axial ion confinement potential $phi_i / T_i >>1 $ as demonstrated in GAMMA-10 [Cho et al. 2005]. Ideal ignition occurs at $T_i=7.6 $ kev from the two-body end loss rate. The rotation rate is well below the sonic value and scales similar to biased wall rotation rates in the LAPD experiments [Horton et al 2005]. Profiles and total energy confinement times are calculated for a proof-of-principle experiment (length $L=7$ m, central cell magnetic field $B=0.28$ T, and radius $a=1$ m) and for a test reactor facility ($L = 30$ m, $B=3$ T, $a= 1.5$ m). We show that the positive dependence of electron radial transport with increasing electron temperature stabilizes the thermal instabilities giving steady state with $ T_i = 30-50$ kev and $T_e =80-200$ kev with a fusion amplification Q of order 1.5 to 3.0 .

Characterization: A2

Comments:

The University of Texas at Austin

Innovative Confinement Concepts Workshop
February 13-16, 2006
Austin, Texas

ICC 2006 UT logo