Connecting the global H-mode power threshold to the local radial electric field at ASDEX Upgrade

ASDEX Upgrade Team

doi:10.1088/1741-4326/ab8777

Connecting the global H-mode power threshold to the local radial electric field at ASDEX Upgrade

ASDEX Upgrade Team

Chair of Plasmarand- und Divertorphysik

Research output: Contribution to journal › Article › peer-review

44 Scopus citations

Abstract

The relation between the macroscopic input power required at ASDEX Upgrade to access the H-mode p_thr and the microscopic E × B shear has been investigated via fast charge-exchange recombination spectroscopy (CXRS) measurements at various toroidal magnetic fields, different electron densities, and in both hydrogen and deuterium plasmas. For the H-mode onset, a threshold in the ν_E×B minimum, an approximation of the E × B shear, has been found. This identifies ν_E×B and not E_r as the important player for the L-H transition. A database of measurements including CXRS, Doppler reflectometry measurements and comparison to neoclassical approximations shows a threshold ν_E×B of (6.7 ± 1.0) km/s ranging over a factor of three in P_thr.

Original language	English
Article number	066026
Journal	Nuclear Fusion
Volume	60
Issue number	6
DOIs	https://doi.org/10.1088/1741-4326/ab8777
State	Published - Jun 2020

Keywords

L-H transition
power threshold
radial electric field
tokamak

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10.1088/1741-4326/ab8777

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title = "Connecting the global H-mode power threshold to the local radial electric field at ASDEX Upgrade",

abstract = "The relation between the macroscopic input power required at ASDEX Upgrade to access the H-mode pthr and the microscopic E × B shear has been investigated via fast charge-exchange recombination spectroscopy (CXRS) measurements at various toroidal magnetic fields, different electron densities, and in both hydrogen and deuterium plasmas. For the H-mode onset, a threshold in the νE×B minimum, an approximation of the E × B shear, has been found. This identifies νE×B and not Er as the important player for the L-H transition. A database of measurements including CXRS, Doppler reflectometry measurements and comparison to neoclassical approximations shows a threshold νE×B of (6.7 ± 1.0) km/s ranging over a factor of three in Pthr.",

keywords = "L-H transition, power threshold, radial electric field, tokamak",

author = "{ASDEX Upgrade Team} and M. Cavedon and G. Birkenmeier and T. P{\"u}tterich and F. Ryter and E. Viezzer and E. Wolfrum and R. Dux and T. Happel and P. Hennequin and U. Plank and U. Stroth and M. Willensdorfer",

note = "Publisher Copyright: {\textcopyright} EURATOM 2020.",

year = "2020",

month = jun,

doi = "10.1088/1741-4326/ab8777",

language = "English",

volume = "60",

journal = "Nuclear Fusion",

issn = "0029-5515",

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T1 - Connecting the global H-mode power threshold to the local radial electric field at ASDEX Upgrade

AU - ASDEX Upgrade Team

AU - Cavedon, M.

AU - Birkenmeier, G.

AU - Pütterich, T.

AU - Ryter, F.

AU - Viezzer, E.

AU - Wolfrum, E.

AU - Dux, R.

AU - Happel, T.

AU - Hennequin, P.

AU - Plank, U.

AU - Stroth, U.

AU - Willensdorfer, M.

PY - 2020/6

Y1 - 2020/6

N2 - The relation between the macroscopic input power required at ASDEX Upgrade to access the H-mode pthr and the microscopic E × B shear has been investigated via fast charge-exchange recombination spectroscopy (CXRS) measurements at various toroidal magnetic fields, different electron densities, and in both hydrogen and deuterium plasmas. For the H-mode onset, a threshold in the νE×B minimum, an approximation of the E × B shear, has been found. This identifies νE×B and not Er as the important player for the L-H transition. A database of measurements including CXRS, Doppler reflectometry measurements and comparison to neoclassical approximations shows a threshold νE×B of (6.7 ± 1.0) km/s ranging over a factor of three in Pthr.

AB - The relation between the macroscopic input power required at ASDEX Upgrade to access the H-mode pthr and the microscopic E × B shear has been investigated via fast charge-exchange recombination spectroscopy (CXRS) measurements at various toroidal magnetic fields, different electron densities, and in both hydrogen and deuterium plasmas. For the H-mode onset, a threshold in the νE×B minimum, an approximation of the E × B shear, has been found. This identifies νE×B and not Er as the important player for the L-H transition. A database of measurements including CXRS, Doppler reflectometry measurements and comparison to neoclassical approximations shows a threshold νE×B of (6.7 ± 1.0) km/s ranging over a factor of three in Pthr.

KW - L-H transition

KW - power threshold

KW - radial electric field

KW - tokamak

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DO - 10.1088/1741-4326/ab8777

M3 - Article

AN - SCOPUS:85085596083

SN - 0029-5515

VL - 60

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 6

M1 - 066026

ER -

Connecting the global H-mode power threshold to the local radial electric field at ASDEX Upgrade

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Keywords

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