Abstract
The ELMs limiting the energy confinement in JT-60U appear when the heating power is high enough compared to the threshold power for the L-H transition. The ELM-free phase is observed when n-bar{sub e} is lower than the threshold density n-bar{sub e}{sup th}. The threshold density n-bar{sub e}{sup th} increases with (B{sub t}{sup 2}/(Rq{sub eff}{sup 2}))l{sub i} which is a measure parameter for the ballooning stability, where q{sub eff} is the effective safety factor at the edge. The edge pressure gradient estimated by n-bar{sub e}{sup th} T{sub i} (95%)/(T{sub i} (95%){sup 0.5}/B{sub p} (a)) is proportional to (B{sub t}{sup 2}/(Rq{sub eff}{sup 2}))l{sub i} which allows us to understand that the ELMs are related to the ballooning instability. A time dependent analysis of the evolution of pressure and current profiles including the boot-strap current shows that the steep edge pressure gradient is close to the marginal value for the high-n ideal ballooning instability at the onset of ELMs. (author).
Kamada, Yutaka;
Sato, Masayasu;
Kikuchi, Mitsuru;
Mori, Masahiro
[1]
- Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment
Citation Formats
Kamada, Yutaka, Sato, Masayasu, Kikuchi, Mitsuru, and Mori, Masahiro.
Onset of ELMs in JT-60U.
Japan: N. p.,
1994.
Web.
Kamada, Yutaka, Sato, Masayasu, Kikuchi, Mitsuru, & Mori, Masahiro.
Onset of ELMs in JT-60U.
Japan.
Kamada, Yutaka, Sato, Masayasu, Kikuchi, Mitsuru, and Mori, Masahiro.
1994.
"Onset of ELMs in JT-60U."
Japan.
@misc{etde_10109249,
title = {Onset of ELMs in JT-60U}
author = {Kamada, Yutaka, Sato, Masayasu, Kikuchi, Mitsuru, and Mori, Masahiro}
abstractNote = {The ELMs limiting the energy confinement in JT-60U appear when the heating power is high enough compared to the threshold power for the L-H transition. The ELM-free phase is observed when n-bar{sub e} is lower than the threshold density n-bar{sub e}{sup th}. The threshold density n-bar{sub e}{sup th} increases with (B{sub t}{sup 2}/(Rq{sub eff}{sup 2}))l{sub i} which is a measure parameter for the ballooning stability, where q{sub eff} is the effective safety factor at the edge. The edge pressure gradient estimated by n-bar{sub e}{sup th} T{sub i} (95%)/(T{sub i} (95%){sup 0.5}/B{sub p} (a)) is proportional to (B{sub t}{sup 2}/(Rq{sub eff}{sup 2}))l{sub i} which allows us to understand that the ELMs are related to the ballooning instability. A time dependent analysis of the evolution of pressure and current profiles including the boot-strap current shows that the steep edge pressure gradient is close to the marginal value for the high-n ideal ballooning instability at the onset of ELMs. (author).}
place = {Japan}
year = {1994}
month = {Aug}
}
title = {Onset of ELMs in JT-60U}
author = {Kamada, Yutaka, Sato, Masayasu, Kikuchi, Mitsuru, and Mori, Masahiro}
abstractNote = {The ELMs limiting the energy confinement in JT-60U appear when the heating power is high enough compared to the threshold power for the L-H transition. The ELM-free phase is observed when n-bar{sub e} is lower than the threshold density n-bar{sub e}{sup th}. The threshold density n-bar{sub e}{sup th} increases with (B{sub t}{sup 2}/(Rq{sub eff}{sup 2}))l{sub i} which is a measure parameter for the ballooning stability, where q{sub eff} is the effective safety factor at the edge. The edge pressure gradient estimated by n-bar{sub e}{sup th} T{sub i} (95%)/(T{sub i} (95%){sup 0.5}/B{sub p} (a)) is proportional to (B{sub t}{sup 2}/(Rq{sub eff}{sup 2}))l{sub i} which allows us to understand that the ELMs are related to the ballooning instability. A time dependent analysis of the evolution of pressure and current profiles including the boot-strap current shows that the steep edge pressure gradient is close to the marginal value for the high-n ideal ballooning instability at the onset of ELMs. (author).}
place = {Japan}
year = {1994}
month = {Aug}
}