Abstract
Edge localized modes (ELMs) are magnetohydrodynamic (MHD) instabilities that cause fast periodic relaxations of the strong edge pressure gradient in tokamak fusion plasmas. A novel diagnostic method allows the extraction of toroidal mode numbers, rotation velocities and spatial information during the ELM cycle including the crash. While mode number branches n = 3-6 and n = 8-10 are dominant just before the ELM crash, during the ELM crash n = 2-5 are observed in typical discharges with type-I ELMs in the tokamak experiment. These findings are compared to results from nonlinear MHD simulations. Although n = 6 is linearly dominant, nonlinear coupling in which n = 1 is particularly important leads to the dominance of n = 3-5 during the ELM crash, in excellent agreement with experimental observations. The simultaneous occurrence of these modes over a wide radial region leads to high stochasticity and thus increased transport.
| Original language | English |
|---|---|
| Article number | 026011 |
| Number of pages | 7 |
| Journal | Nuclear Fusion |
| Volume | 58 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 1 Feb 2018 |
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Keywords
- Edge localized mode
- JOREK
- Mode number
- Nonlinear
- Plasma
Cite this
}
Nonlinear coupling induced toroidal structure of edge localized modes. / Mink, A. F.; Hoelzl, M.; Wolfrum, E.; Orain, F.; Dunne, M.; Lessig, A.; Pamela, S.; Manz, P.; Maraschek, M.; Huijsmans, G.T.A.; Becoulet, M.; Laggner, F. M.; Cavedon, M.; Lackner, K.; Günter, S.; Stroth, U.
In: Nuclear Fusion, Vol. 58, No. 2, 026011, 01.02.2018.Research output: Contribution to journal › Article › Academic › peer-review
TY - JOUR
T1 - Nonlinear coupling induced toroidal structure of edge localized modes
AU - Mink, A. F.
AU - Hoelzl, M.
AU - Wolfrum, E.
AU - Orain, F.
AU - Dunne, M.
AU - Lessig, A.
AU - Pamela, S.
AU - Manz, P.
AU - Maraschek, M.
AU - Huijsmans, G.T.A.
AU - Becoulet, M.
AU - Laggner, F. M.
AU - Cavedon, M.
AU - Lackner, K.
AU - Günter, S.
AU - Stroth, U.
PY - 2018/2/1
Y1 - 2018/2/1
N2 - Edge localized modes (ELMs) are magnetohydrodynamic (MHD) instabilities that cause fast periodic relaxations of the strong edge pressure gradient in tokamak fusion plasmas. A novel diagnostic method allows the extraction of toroidal mode numbers, rotation velocities and spatial information during the ELM cycle including the crash. While mode number branches n = 3-6 and n = 8-10 are dominant just before the ELM crash, during the ELM crash n = 2-5 are observed in typical discharges with type-I ELMs in the tokamak experiment. These findings are compared to results from nonlinear MHD simulations. Although n = 6 is linearly dominant, nonlinear coupling in which n = 1 is particularly important leads to the dominance of n = 3-5 during the ELM crash, in excellent agreement with experimental observations. The simultaneous occurrence of these modes over a wide radial region leads to high stochasticity and thus increased transport.
AB - Edge localized modes (ELMs) are magnetohydrodynamic (MHD) instabilities that cause fast periodic relaxations of the strong edge pressure gradient in tokamak fusion plasmas. A novel diagnostic method allows the extraction of toroidal mode numbers, rotation velocities and spatial information during the ELM cycle including the crash. While mode number branches n = 3-6 and n = 8-10 are dominant just before the ELM crash, during the ELM crash n = 2-5 are observed in typical discharges with type-I ELMs in the tokamak experiment. These findings are compared to results from nonlinear MHD simulations. Although n = 6 is linearly dominant, nonlinear coupling in which n = 1 is particularly important leads to the dominance of n = 3-5 during the ELM crash, in excellent agreement with experimental observations. The simultaneous occurrence of these modes over a wide radial region leads to high stochasticity and thus increased transport.
KW - Edge localized mode
KW - JOREK
KW - Mode number
KW - Nonlinear
KW - Plasma
UR - http://www.scopus.com/inward/record.url?scp=85040697092&partnerID=8YFLogxK
U2 - 10.1088/1741-4326/aa98f7
DO - 10.1088/1741-4326/aa98f7
M3 - Article
AN - SCOPUS:85040697092
VL - 58
JO - Nuclear Fusion
JF - Nuclear Fusion
SN - 0029-5515
IS - 2
M1 - 026011
ER -