Global energy confinement scaling predictions for the kinetically stabilized tandem mirror

Journal Article · Sat Apr 15 00:00:00 EDT 2006 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.2188913· OSTI ID:20782749

Pratt, J; Horton, W ^[1]

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1. Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)

Transport is studied for the kinetically stabilized tandem mirror, an attractive magnetic confinement device for achieving a steady-state burning plasma. For a magnetohydrodynamic stable system, three different radial transport models with Bohm, gyro-Bohm, and electron temperature gradient (ETG) scaling are derived. 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 radially trapped particle modes and ETG transport losses. The radial transport equations are analyzed, taking into account the Pastukhov energy and particle end losses. For mirror ratio R{sub m}=9 and a large density ratio between plug and central cell regions, there is a high axial ion confinement potential {phi}{sub i}/T{sub i}>>1, as demonstrated in the GAMMA-10 by Cho et al. [Nucl. Fusion 45, 1650 (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). For these parameter sets, radial loss dominates the end losses except in the low temperature periphery. In the limit of negligible radial losses, ideal ignition occurs at T{sub i}=7.6 keV from the two-body power end losses. The transport suppressing rotation rate is well below the sonic value and scales similarly to biased wall rotation rates in the Large Plasma Device experiments [Horton et al., Phys. Plasmas 12, 022303 (2005)]. Simulation results show that the positive dependence of electron radial transport with increasing electron temperature stabilizes the thermal instabilities giving steady state with T{sub i}=30-60 keV and T{sub e}=50-150 keV with a fusion amplification Q of order 1.5 to 5.0.

• OSTI ID: 20782749
• Journal Information: Physics of Plasmas, Vol. 13, Issue 4; Other Information: DOI: 10.1063/1.2188913; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COMPUTERIZED SIMULATION
ELECTRON TEMPERATURE
ELECTRONS
END EFFECTS
GAMMA 10 DEVICES
ION TEMPERATURE
IONS
KEV RANGE
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
MIRROR RATIO
PLASMA
PLASMA DRIFT
PLASMA INSTABILITY
PLASMA POTENTIAL
PLASMA SIMULATION
RADIATION TRANSPORT
ROTATION
STEADY-STATE CONDITIONS
STELLARATORS
TEMPERATURE GRADIENTS
TOKAMAK DEVICES
TRANSPORT THEORY
TRAPPING
TURBULENCE
TWO-BODY PROBLEM