First measurements of the particle confinement in a reversed field pinch by the laser ablation method

Carolan, P. G.; Patel, A.; Sexton, M. C.; Walsh, M. J.

doi:10.1088/0029-5515/30/12/015

Cited by 7 publications

(11 citation statements)

References 12 publications

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“…Even though there exists a large number of theoretical and experimental studies on tokamaks and stellarators, there is a paucity of time-resolved and spatially localized information about impurities in RFP plasmas. Impurity studies in RFPs have been supported by line integrated emission measurements [9][10][11][12]. A large range in the transport parameters in different machines is found in these works.…”

mentioning

confidence: 78%

Behaviour of carbon and boron impurities in the Madison Symmetric Torus

Kumar¹,

Hartog²,

Magee³

et al. 2011

Plasma Phys. Control. Fusion

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Temporally and spatially resolved measurements of carbon and boron impurity density are obtained in the reversed field pinch (RFP) for the first time. It is observed that, unlike in tokamaks and stellarators, the RFP does not exhibit a centrally peaked impurity profile in either standard plasmas where field lines have some degree of stochasticity, or improved confinement discharges where there exist well-nested flux surfaces for a substantial fraction of the plasma volume. Results from improved confinement discharges also indicate an outward convection of impurities from the core of the plasma.

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mentioning

confidence: 78%

Behaviour of carbon and boron impurities in the Madison Symmetric Torus

Kumar¹,

Hartog²,

Magee³

et al. 2011

Plasma Phys. Control. Fusion

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“…For the typical confinement properties in T P E 1RM20, carbon is better than boron as a probe impurity since the helium-like charge state C V has a longer ionization time than the equivalent of B IV [6] (see also Section 5.1). Boron was chosen as a probe impurity for the present experiment, however, because the use of carbon ablation might coat the vacuum vessel wall and alter the recycling condition for particle balance.…”

Section: The Laser Ablation and Spectroscopy Systemmentioning

confidence: 99%

“…The first measurement of particle confinement in an RFP plasma was reported in Ref. [6]. The authors of that paper used the laser ablation technique with carbon and boron as probe impurities.…”

Section: Introductionmentioning

confidence: 99%

Particle confinement in a reversed field pinch plasma

Yagi¹,

Baig²,

Carraro³

et al. 1997

Nucl. Fusion

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The particle confinement time of boron, tau B, is studied in the TPE-1RM20 reversed field pinch plasma by means of a laser ablation technique. The experimental conditions were as follows: pinch parameter, Theta , and plasma current, Ip, are scanned, and tau B obtained from a zero dimensional approximation is compared with the energy confinement time, tau E. The results show that tau B increases almost linearly with tau E, and the implication of this is discussed in terms of energy loss channels. The increase of tau B with Theta supports the recently obtained improved confinement at high Theta . Laser ablation results are compared with the particle confinement time of deuterium, tau p, from the Dalpha line spectrum measurement. It is shown that tau b approximately= tau p, which indicates a weak mass dependence in particle transport. Numerical simulation is also conducted and compared on a one dimensional basis with the experimentally obtained spatial distribution of the line emission intensity of the boron impurity injected by the laser ablation. The result shows reasonable agreement with experiment

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“…In this approach, transport coefficients can be measured by observing the reaction of the plasma parameters to a perturbation; however, these are transient values and they can be different from those measured with steady state techniques [2]. These perturbations can be spontaneously generated, such as sawtooth crashes, edge localized modes or other magnetohydrodynamic phenomena [3][4][5], or they can be actively induced by means of localized radio frequency heating, laser blow-off of impurities and pellet injection [6][7][8], for example. Once generated, the propagation of the perturbation allows the study of the diffusivity properties of the plasma.…”

Section: Introductionmentioning

confidence: 99%

Cold pulse propagation in a reversed-field pinch

et al. 2007

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The cold pulse propagation is a powerful tool for the study of heat transport and the determination of perturbative electron heat diffusivity . In this paper the experimental study of cold pulses generated by pellet injection in a reversed-field pinch device is described. The most common phenomenology is an inward cold pulse propagation, from the edge to the core; however, we will describe that outward propagation can occur if the pellet ablates up to the plasma centre. A model to simulate the dynamics of the pulse (i.e. the relation between the arrival time of the pulse and its radial position) has been developed. With this model it is possible to explain the cold pulse phenomenologies as well as to estimate in the plasma core. The heat diffusivity in standard and enhanced confinement plasmas has been determined and compared; in standard regimes is three times larger than in enhanced confinement regimes. Finally, it has been possible to confirm a scaling between diffusivity and magnetic stochasticity.

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First measurements of the particle confinement in a reversed field pinch by the laser ablation method

Cited by 7 publications

References 12 publications

Behaviour of carbon and boron impurities in the Madison Symmetric Torus

Behaviour of carbon and boron impurities in the Madison Symmetric Torus

Particle confinement in a reversed field pinch plasma

Cold pulse propagation in a reversed-field pinch

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