Critical energetic particle distribution in phase space for the Alfvén eigenmode burst with global resonance overlap

Abstract 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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Numerical Study on Particle Distribution in Longitudinal Phase Space and Beam Current Profile using Compact Electron Beam Simulator for Heavy Ion Inertial Fusion

IEEJ Transactions on Power and Energy ◽

10.1541/ieejpes.137.344 ◽

2017 ◽

Vol 137 (5) ◽

pp. 344-348

Author(s):

Takashi Kikuchi ◽

Yasuo Sakai ◽

Jun Hasegawa ◽

Kazuhiko Horioka ◽

Kazumasa Takahashi ◽

...

Keyword(s):

Electron Beam ◽

Phase Space ◽

Particle Distribution ◽

Numerical Study ◽

Heavy Ion ◽

Beam Current ◽

Inertial Fusion ◽

Current Profile ◽

Longitudinal Phase

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CIRCUMSOLAR ENERGETIC PARTICLE DISTRIBUTION ON 2011 NOVEMBER 3

The Astrophysical Journal ◽

10.1088/0004-637x/799/1/55 ◽

2015 ◽

Vol 799 (1) ◽

pp. 55 ◽

Cited By ~ 56

Author(s):

R. Gómez-Herrero ◽

N. Dresing ◽

A. Klassen ◽

B. Heber ◽

D. Lario ◽

...

Keyword(s):

Energetic Particle ◽

Particle Distribution

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Use of projectional phase space data to infer a 4D particle distribution

Laser and Particle Beams ◽

10.1017/s0263034602211040 ◽

2003 ◽

Vol 21 (1) ◽

pp. 17-20 ◽

Cited By ~ 11

Author(s):

A. FRIEDMAN ◽

D.P. GROTE ◽

C.M. CELATA ◽

J.W. STAPLES

Keyword(s):

Experimental Data ◽

Phase Space ◽

Particle Distribution ◽

National Laboratory ◽

Two Dimensional ◽

High Current ◽

Current Experiment ◽

Axial Coordinate ◽

Small Set ◽

Space Data

We consider beams that are described by a four-dimensional (4D) transverse distribution f (x, y, x′, y′), where x′ ≡ px /pz and z is the axial coordinate. A two-slit scanner is commonly employed to measure, over a sequence of shots, a two-dimensional (2D) projection of such a beam's phase space, for example, f (x, x′). Another scanner might yield f (y, y′) or, using crossed slits, f (x, y). A small set of such 2D scans does not uniquely specify f (x, y, x′, y′). We have developed “tomographic” techniques to synthesize a “reasonable” set of particles in a 4D phase space having 2D densities consistent with the experimental data. We briefly summarize one method and describe progress in validating it, using simulations of the High Current Experiment at Lawrence Berkeley National Laboratory.

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