Application of the Scrape-Off-Layer Fast Ion (SOLFI) code to assess particle motion in mirrors and tokamaks

Fuente: arXiv
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Main Authors: Zhang, X., Lopez, N. A., Nelson, A. O., Rondini, L., Poli, F. M.
Format: Preprint
Published: 2021
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_version_ 1866914910292672512
author Zhang, X.
Lopez, N. A.
Nelson, A. O.
Rondini, L.
Poli, F. M.
author_facet Zhang, X.
Lopez, N. A.
Nelson, A. O.
Rondini, L.
Poli, F. M.
contents This paper introduces the Scrape-Off-Layer Fast Ion (SOLFI) code, which is a new and versatile full-orbit Monte Carlo particle tracer developed to follow fast ion orbits inside and outside the separatrix in tokamaks. SOLFI is benchmarked in a simple straight mirror geometry, showing that the code conserves particle energy and magnetic moment, obtains the correct passing boundary for particles moving in the magnetic mirror field with an imposed electrostatic field, and correctly observes equal ion and electron current at the ambipolar potential predicted from analytical theory. This result has consequences for collisionless scrape-off-layers in spherical tokamaks. We then utilize SOLFI for fundamental physics studies in novel tokamak geometries, exploring the effect of shaping on the trapped particle fraction and bounce locations in tokamaks and demonstrating that negative triangularity can be used to maximize the fraction of particles bouncing in the good-curvature region, potentially leading to enhanced confinement.
format Preprint
id arxiv_https___arxiv_org_abs_2104_07547
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Application of the Scrape-Off-Layer Fast Ion (SOLFI) code to assess particle motion in mirrors and tokamaks
Zhang, X.
Lopez, N. A.
Nelson, A. O.
Rondini, L.
Poli, F. M.
Plasma Physics
Computational Physics
This paper introduces the Scrape-Off-Layer Fast Ion (SOLFI) code, which is a new and versatile full-orbit Monte Carlo particle tracer developed to follow fast ion orbits inside and outside the separatrix in tokamaks. SOLFI is benchmarked in a simple straight mirror geometry, showing that the code conserves particle energy and magnetic moment, obtains the correct passing boundary for particles moving in the magnetic mirror field with an imposed electrostatic field, and correctly observes equal ion and electron current at the ambipolar potential predicted from analytical theory. This result has consequences for collisionless scrape-off-layers in spherical tokamaks. We then utilize SOLFI for fundamental physics studies in novel tokamak geometries, exploring the effect of shaping on the trapped particle fraction and bounce locations in tokamaks and demonstrating that negative triangularity can be used to maximize the fraction of particles bouncing in the good-curvature region, potentially leading to enhanced confinement.
title Application of the Scrape-Off-Layer Fast Ion (SOLFI) code to assess particle motion in mirrors and tokamaks
topic Plasma Physics
Computational Physics
url https://arxiv.org/abs/2104.07547