Details

Autor(en) / Beteiligte

• Hollmann, E.M.
• Commaux, N.
• Moyer, R.A.
• Parks, P.B.
• Austin, M.E.
• Bykov, I.
• Cooper, C.
• Eidietis, N.W.
• O'Mullane, M.
• Paz-Soldan, C.
• Rudakov, D.L.
• Shiraki, D.

Titel

Use of Ar pellet ablation rate to estimate initial runaway electron seed population in DIII-D rapid shutdown experiments

Ist Teil von

• Nuclear fusion, 2017-01, Vol.57 (1), p.16008

Ort / Verlag

United States: IOP Publishing

Erscheinungsjahr

2017

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Small (2-3 mm, 0.9-2 Pa · m3) argon pellets are used in the DIII-D tokamak to cause rapid shutdown (disruption) of discharges. The Ar pellet ablation is typically found to be much larger than expected from the thermal plasma electron temperature alone; the additional ablation is interpreted as being due to non-thermal runaway electrons (REs) formed during the pellet-induced temperature collapse. Simple estimates of the RE seed current using the enhanced ablation rate give values of order 1-10 kA, roughly consistent with estimates based on avalanche theory. Analytic estimates of the RE seed current based on the Dreicer formula tend to significantly underestimate it, while estimates based on the hot tail model significantly overestimate it.