The pellet rocket effect in magnetic confinement fusion plasmas

Pellets of frozen material travelling into a magnetically confined fusion plasma are accelerated by the so-called pellet rocket effect. The non-uniform plasma heats the pellet ablation cloud asymmetrically, producing pressure-driven, rocket-like propulsion of the pellet. We present a semi-analytical...

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Bibliographic Details
Published in:arXiv.org 2024-12
Main Authors: Guth, Nico J, Vallhagen, Oskar, Helander, Per, Pusztai, Istvan, Newton, Sarah L, Fülöp, Tünde
Format: Article
Language:English
Subjects:
Confinement
Nonuniform plasmas
Pellets
Pressure effects
Tokamak devices
Online Access:Get full text
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Summary:Pellets of frozen material travelling into a magnetically confined fusion plasma are accelerated by the so-called pellet rocket effect. The non-uniform plasma heats the pellet ablation cloud asymmetrically, producing pressure-driven, rocket-like propulsion of the pellet. We present a semi-analytical model of this process by perturbing a spherically symmetric ablation model. Predicted pellet accelerations match experimental estimates in current tokamaks (\(\sim 10^5 \;\rm m/s^2\)). Projections for ITER high-confinement scenarios (\(\sim 10^6 \;\rm m/s^2\)) indicate significantly shorter pellet penetration than expected without this effect, which could limit the effectiveness of disruption mitigation.
ISSN:2331-8422