Alternating Current Tokamak Reactor with Long Pulses

Mitarai, O.; Wolfe, S.; Hirose, Akira; Skarsgard, H. M.

doi:10.13182/fst89-a25357

Cited by 23 publications

(9 citation statements)

References 11 publications

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“…where P oh is the Ohmic heating power density, P h is the auxiliary heating power density, P a is the alpha particle heating density expressed by P a = n 2 (ov) DT q a /4, n is the deuterium and tritium plasma density, (ov) DT is the D-T fusion rate, q a = 3.52 MeV is the fusion alpha energy, P L = 3nKT/r E is the plasma energy loss, T is the plasma temperature, T E is the energy confinement time, P b = 1.5 x 10' 38 Z eff n 2 Vf is the bremsstrahlung energy loss and Z eff is the effective ionic charge. For steady state conditions and uniform density and temperature profiles [9], Eq. (2.1) becomes…”

Section: Generalized Ignition Contour Mapmentioning

confidence: 99%

“…For the larger fusion reactor ACTR [8], which has recently been considered for AC tokamak operation using an alternating plasma current, with the parameters R = 1000 cm, a = 200 cm, I p = 10 x 10 6 A and K = 1.8, [PhtrllACTR = 0.325 MW/m 3 -s 2 is obtained, which is also less than the height of the saddle point. In this sense, there is an 'ignition barrier' which hinders these machines from reaching ignition, as shown in the figures.…”

Section: 3)mentioning

confidence: 99%

“…The ignition requirement corresponds to surmounting the saddle point on the generalized ignition contour map. We also derive the scaling law required to satisfy this criterion with an acceptable heating power and discuss the operation path on the generalized ignition contour map for the INTOR [7] and ACTR [8] tokamaks. Assuming T E a 1/Ph,, the ignition criterion is satisfied with 7 < 0.3 for INTOR and y < 0.44 for ACTR, with Z eff = 1, Va = 0.8, P H = 100 MW, and uniform plasma temperature and density profiles (rj a is the fraction of the alpha heating power trapped in the plasma, P H is the auxiliary heating power).…”

Section: Introductionmentioning

confidence: 99%

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Generalized ignition contour map and scaling law requirement for reaching ignition in a tokamak reactor

1988

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The paper presents a method for determining the potential of a reactor design to reach ignition conditions. The method makes use of a 'generalized' contour map with a three-dimensional (P h ,T|, nr E , T) representation. On this map, the height of P h j\ (with P hl the total heating power density and T E the energy confinement time) at the saddle point provides a criterion for reaching ignition. By a combination of this map with Goldston's L-mode scaling law, it is found that the operating point of the tokamak moves along a line of constant P h ,T|; the value of P h ,r| for H-mode scaling can be increased with auxiliary heating power so that the saddle point can be reached. Confinement degradation effects due to alpha particle heating can be treated by replacing P h I r| by (P h , + f a i) a P a )T| (f o is the fraction of the alpha particle heating P a causing confinement degradation, rj a is the fraction of the alpha heating power trapped in the plasma).The saddle point becomes higher and shifts to a larger nr E regime by this alpha degradation effect.

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Section: Generalized Ignition Contour Mapmentioning

confidence: 99%

Section: 3)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Generalized ignition contour map and scaling law requirement for reaching ignition in a tokamak reactor

1988

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“…[2] However, the achievement of long flat-top plasma current AC discharges can degrade the importance of this effect. [3] The potential problems associated with thermal fatigue of a first wall and a blanket and with mechanical fatigue of the toroidal coil may be relaxed by long-pulse operation with a half-cycle period of several hours using a large Ohmic transformer flux, perhaps > 1000 Vs. Thus AC operation will be a very important mode of operation for a next-step device such as the international thermonuclear experimental reactor (ITER) and commercial tokamak reactors as well.…”

Section: Introductionmentioning

confidence: 99%

AC operation and runaway electron behaviour in HT-7 tokamak

Hong-Wei¹,

Hu²,

Zhou³

et al. 2010

Chinese Phys. B

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Operation of HT-7 tokamak in a multicycle alternating square wave plasma current regime is reported. A set of AC operation experiments, including LHW heating to enhance plasma ionization during the current transition and current sustainment, is described. The behaviour of runaway electrons is analysed by four HXR detectors tangentially viewing the plasma in the equatorial plane, within energy ranges 0.3-1.2 MeV and 0.3-7 MeV, separately. High energy runaway electrons (∼MeV) are found to circulate predominantly in the opposite direction to the plasma current, while the number of low energy runaway electrons (∼tens to hundreds of keV) circulating along the plasma current is comparable to that in the direction opposite to the plasma current. AC operation with lower hybrid current drive (LHCD) is observed to have an additional benefit of suppressing the runaway electrons if the drop of the loop voltage is large enough.

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“…Alternating current (AC) quasi-steady state operation is an alternative to pure steady state operation in D-T and D-He tokamak fusion reactors including the Next Step Device [1][2][3][4][5][6]. This mode of operation is attractive because of its ability to generate a continuous electrical energy output with a minimum thermal storage unit [4].…”

Section: Introductionmentioning

confidence: 99%

Investigation of Plasma Equilibrium in the Saskatchewan Torus‐Modified (STOR‐M) during Alternating Current Operation

Singh

Morelli

Xiao

et al. 2006

Contrib. Plasma Phys.

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An experiment to investigate the source of plasma equilibrium of the residual plasma at zero cross over of plasma current is presented. The role of limiter in providing this equilibrium by short circuiting the electric field developed due to the toroidal drifts is examined by measuring the current flowing through the limiter. The role of a fast poloidal rotation observed by a set of Mach probes, during zero cross over is also examined in providing the equilibrium.

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Alternating Current Tokamak Reactor with Long Pulses

Cited by 23 publications

References 11 publications

Generalized ignition contour map and scaling law requirement for reaching ignition in a tokamak reactor

Generalized ignition contour map and scaling law requirement for reaching ignition in a tokamak reactor

AC operation and runaway electron behaviour in HT-7 tokamak

Investigation of Plasma Equilibrium in the Saskatchewan Torus‐Modified (STOR‐M) during Alternating Current Operation

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