Observation of Marfes in the Wendelstein 7-X stellarator with inboard limiters

U. Wenzel; C. Biedermann; G. Kocsis; T. Szepesi; B. D. Blackwell; S. Klose; J. Knauer; M. Krychowiak; L. Stephey; O. Schmitz; J. Harris; R. König; T. S. Pedersen

doi:10.1088/1741-4326/aacb86

Observation of Marfes in the Wendelstein 7-X stellarator with inboard limiters

U. Wenzel, C. Biedermann, G. Kocsis, T. Szepesi, B. D. Blackwell, S. Klose, J. Knauer, M. Krychowiak, L. Stephey, O. Schmitz, J. Harris, R. König, T. S. Pedersen

Power Exhaust and Particle Control

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5 Scopus citations

Abstract

In the first operational campaign of the Wendelstein 7-X (W7-X) stellarator we observed Marfe-like radiation belts at the plasma edge. We describe and analyze the behaviour of these radiation belts, especially with respect to the high density inside the belt, with a set of suitable diagnostics. We present evidence suggesting that these Marfe-like radiation belts are triggered by a drop of the edge temperature below 30 eV. From this observation we draw the conclusion that the physical cause of Marfes in tokamaks and Marfe-like radiation belts in W7-X is the same, namely radiative condensation. Furthermore, both exhibit the device symmetry, i.e. axisymmetry in a tokamak and the fivefold stellarator symmetry in W7-X.

Original language	English
Article number	096025
Journal	Nuclear Fusion
Volume	58
Issue number	9
DOIs	https://doi.org/10.1088/1741-4326/aacb86
State	Published - Jul 11 2018

Funding

This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement No 633053. The views and opinions expressed herein do not necessarily reflect those of the European Commission.

Keywords

Marfe
radiative condensation
stellarator

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10.1088/1741-4326/aacb86

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@article{09ef8fe8bf8f4c1ab4c355e2e8427d4d,

title = "Observation of Marfes in the Wendelstein 7-X stellarator with inboard limiters",

abstract = "In the first operational campaign of the Wendelstein 7-X (W7-X) stellarator we observed Marfe-like radiation belts at the plasma edge. We describe and analyze the behaviour of these radiation belts, especially with respect to the high density inside the belt, with a set of suitable diagnostics. We present evidence suggesting that these Marfe-like radiation belts are triggered by a drop of the edge temperature below 30 eV. From this observation we draw the conclusion that the physical cause of Marfes in tokamaks and Marfe-like radiation belts in W7-X is the same, namely radiative condensation. Furthermore, both exhibit the device symmetry, i.e. axisymmetry in a tokamak and the fivefold stellarator symmetry in W7-X.",

keywords = "Marfe, radiative condensation, stellarator",

author = "U. Wenzel and C. Biedermann and G. Kocsis and T. Szepesi and Blackwell, {B. D.} and S. Klose and J. Knauer and M. Krychowiak and L. Stephey and O. Schmitz and J. Harris and R. K{\"o}nig and Pedersen, {T. S.}",

note = "Publisher Copyright: {\textcopyright} EURATOM 2018.",

year = "2018",

month = jul,

day = "11",

doi = "10.1088/1741-4326/aacb86",

language = "English",

volume = "58",

journal = "Nuclear Fusion",

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TY - JOUR

T1 - Observation of Marfes in the Wendelstein 7-X stellarator with inboard limiters

AU - Wenzel, U.

AU - Biedermann, C.

AU - Kocsis, G.

AU - Szepesi, T.

AU - Blackwell, B. D.

AU - Klose, S.

AU - Knauer, J.

AU - Krychowiak, M.

AU - Stephey, L.

AU - Schmitz, O.

AU - Harris, J.

AU - König, R.

AU - Pedersen, T. S.

PY - 2018/7/11

Y1 - 2018/7/11

N2 - In the first operational campaign of the Wendelstein 7-X (W7-X) stellarator we observed Marfe-like radiation belts at the plasma edge. We describe and analyze the behaviour of these radiation belts, especially with respect to the high density inside the belt, with a set of suitable diagnostics. We present evidence suggesting that these Marfe-like radiation belts are triggered by a drop of the edge temperature below 30 eV. From this observation we draw the conclusion that the physical cause of Marfes in tokamaks and Marfe-like radiation belts in W7-X is the same, namely radiative condensation. Furthermore, both exhibit the device symmetry, i.e. axisymmetry in a tokamak and the fivefold stellarator symmetry in W7-X.

AB - In the first operational campaign of the Wendelstein 7-X (W7-X) stellarator we observed Marfe-like radiation belts at the plasma edge. We describe and analyze the behaviour of these radiation belts, especially with respect to the high density inside the belt, with a set of suitable diagnostics. We present evidence suggesting that these Marfe-like radiation belts are triggered by a drop of the edge temperature below 30 eV. From this observation we draw the conclusion that the physical cause of Marfes in tokamaks and Marfe-like radiation belts in W7-X is the same, namely radiative condensation. Furthermore, both exhibit the device symmetry, i.e. axisymmetry in a tokamak and the fivefold stellarator symmetry in W7-X.

KW - Marfe

KW - radiative condensation

KW - stellarator

UR - http://www.scopus.com/inward/record.url?scp=85051197526&partnerID=8YFLogxK

U2 - 10.1088/1741-4326/aacb86

DO - 10.1088/1741-4326/aacb86

M3 - Article

AN - SCOPUS:85051197526

SN - 0029-5515

VL - 58

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 9

M1 - 096025

ER -

Observation of Marfes in the Wendelstein 7-X stellarator with inboard limiters

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Keywords

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