Ion cyclotron heating in TMX-U

Dimonte, Guy; Molvik, A.W.; Barter, J. D.; Cummins, W.F.; Falabella, S.; Poulsen, Peter Behrensdorff; Romesser, T.

doi:10.1088/0029-5515/27/12/001

Cited by 14 publications

(17 citation statements)

References 18 publications

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“…The heating and fuelling systems include neutral beam injection, electron cyclotron heating (ECH) [22], ion cyclotron heating (ICH) [23,24], and gas boxes and puffers. The number of neutral beams at each location before June 1986 is given by the first number in parentheses in Fig.…”

Section: Plasma Heating Fuelling and Diagnosticsmentioning

confidence: 99%

Experimental beta limit in an average minimum-B tandem mirror

Molvik¹,

Casper²,

Futch³

1990

Nucl. Fusion

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High density (non-thermal-barrier) operation in the Tandem Mirror Experiment Upgrade (TMX-U) is found to be restricted by a stability limit. This limit is observed in the ratio of the neutral beam sustained central cell beta βc to the hot ion beta βih in the minimum-B anchor cells at both ends of the central cell, qualitatively consistent with a flute interchange stability limit. The ratio is βc/βih = 5, over the range of 0.03 ≤ βc ≤ 0.22, with no apparent reduction due to ballooning at high βc. This is a factor of six below the standard magnetohydrodynamic (MHD) m = 1 stability theory prediction of βc/βih = 33 at βc ≤ 0.1, where ballooning corrections to flute modes are small. The discrepancy could be due to approximations in the theory; however, experimental data indicate that the stability limit is due to drift wave turbulence or to large-m MHD flute or ballooning modes. The experimental beta limit is nearly independent of the hot electron beta in the anchor cells, which is compatible with theoretical predictions that the hot electron beta will decouple from MHD activity.

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Section: Plasma Heating Fuelling and Diagnosticsmentioning

confidence: 99%

Experimental beta limit in an average minimum-B tandem mirror

Molvik¹,

Casper²,

Futch³

1990

Nucl. Fusion

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“…Its radiation and heating properties are described in Ref. [1]. With 100 kW of power, the passing ion collisionality has been reduced tenfold for plasma densities, n -(1-2) x 10 l2 cm' 3 , characteristic of thermal barrier operation.…”

Section: Experimental Configurationmentioning

confidence: 99%

“…Auxiliary heating has been used in many fusion oriented devices to study particle and energy confinement at higher particle energies, more relevant to the regime of a fusion reactor. In this paper, we present the results of numerical modelling of ion cyclotron heating (ICH) in the centre cell of the Tandem Mirror Experiment Upgrade (TMX-U) [1] at Lawrence Livermore National Laboratory. In TMX-U the goals of ICH were to reduce the number and collisionality of ions passing into the end cell to help prevent collisional filling of the electrostatic thermal barrier and to increase the centre-cell density to improve neutral beam absorption.…”

Section: Introductionmentioning

confidence: 99%

“…has been discussed in an earlier paper [1]. Here we focus on the ion heating by using a Monte Carlo code where an ensemble of test particles are subjected to collisions and wave heating [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…The TMX-U device is described in detail in Ref. [1]. The plasma density was in the range of (0.3-3) x 10 12 cm" 3 and the RF power was ~ 100 kW.…”

Section: Introductionmentioning

confidence: 99%

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Simulation of ion confinement during ion cyclotron heating in the TMX-U tandem mirror

Rognlien¹,

Campbell²,

Dimonte³

et al. 1989

Nucl. Fusion

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Particle and energy confinement of ions during ion cyclotron heating (ICH) in the centre cell of a tandem mirror is simulated by a Monte Carlo code. The interaction of the ion cyclotron wave with the ions is calculated using reduced equations of motion, and Coulomb collisions are modelled using a Monte Carlo algorithm. An axial electrostatic potential profile is generated by an iteration procedure, assuming Maxwellian electrons. The axial profile of neutral gas which fuels the ions from a localized gas box is determined from a neutral particle Monte Carlo code. Steady state calculations are reported for the Tandem Mirror Experiment Upgrade (TMX-U). The calculated energy confinement time τE is about twice that measured for off-midplane fuelling. The calculated τE can be decreased to the experimental value by either introducing extra gas at the ICH antenna to model the effect of ions striking the antenna or assuming anomalous radial loss. However, the enhanced radial loss also increases the end loss current well above that measured. Experimental and calculated τE agree more closely for midplane fuelling with heating from one antenna.

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Ion cyclotron resonance heating (ICRH) systems for the Keda Mirror with AXisymmetry (KMAX)

Liu

Lin

et al. 2017

Review of Scientific Instruments

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In this paper, we describe the engineering work involved in constructing two ion cyclotron resonance heating (ICRH) systems for use in the Keda Mirror with AXisymmetry tandem mirror experiment. Because they offer an effective and robust heating method, ICRH systems have been widely used in a variety of plasma experiments. The goal of our system is to heat the hydrogen plasma contained in the central cell using the fundamental ion cyclotron frequency. Both systems can deliver a radiofrequency power of ∼120 kW with adjustable operating frequencies that are tuned to be slightly lower than their local ion cyclotron frequencies. Two types of antennas are installed in the central cell in an attempt to launch both slow and fast waves. The heating mechanism is reliant on the magnetic beach effect for slow waves.

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Ion cyclotron heating in TMX-U

Cited by 14 publications

References 18 publications

Experimental beta limit in an average minimum-B tandem mirror

Experimental beta limit in an average minimum-B tandem mirror

Simulation of ion confinement during ion cyclotron heating in the TMX-U tandem mirror

Ion cyclotron resonance heating (ICRH) systems for the Keda Mirror with AXisymmetry (KMAX)

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