Preferential confinement and field-aligned acceleration of energetic ions in a reversed field pinch

Anderson, J. K.; Kim, J.; Sarff, J. S.; Belykh, V. V.; Давыденко, В. И.; Ivanov, A. A.; Polosatkin, S. V.

doi:10.1063/1.4964186

Cited by 1 publication

(1 citation statement)

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“…A similar effect was also observed in sawtooth crashes in a reversed-field pinch. [47,48]. Further experiments and analysis is needed to confirm this result.…”

Section: Redistribution Of Fast Ions By a Sawtooth Crash At Asdex-upg...mentioning

confidence: 89%

Orbit tomography of energetic particle distribution functions

Stagner¹,

Heidbrink²,

Salewski³

et al. 2022

Nucl. Fusion

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Both fast ions and runaway electrons are described by distribution functions, the understanding of which are of critical importance for the success of future fusion devices such as ITER. Typically, energetic particle diagnostics are only sensitive to a limited subsection of the energetic particle phase-space which is often insufficient for model validation. However, previous publications show that multiple measurements of a single spatially localized volume can be used to reconstruct a distribution function of the energetic particle velocity-space by using the diagnostics' velocity-space weight functions, i.e. Velocity-space Tomography. In this work we use the recently formulated orbit weight functions to remove the restriction of spatially localized measurements and present Orbit Tomography, which is used to reconstruct the 3D phase-space distribution of all energetic particle orbits in the plasma. Through a transformation of the orbit distribution, the full energetic particle distribution function can be determined in the standard {energy,pitch,r,z}-space. We benchmark the technique by reconstructing the fast-ion distribution function of an MHD-quiescent DIII-D discharge using synthetic and experimental FIDA measurements. We also use the method to study the redistribution of fast ions during a sawtooth crash at ASDEX Upgrade using FIDA measurements. Finally, a comparison between the Orbit Tomography and Velocity-space Tomography is shown.

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“…A similar effect was also observed in sawtooth crashes in a reversed-field pinch. [47,48]. Further experiments and analysis is needed to confirm this result.…”

Section: Redistribution Of Fast Ions By a Sawtooth Crash At Asdex-upg...mentioning

confidence: 89%