Hot tail runaway electron generation in tokamak disruptions

2008 ◽  
Vol 15 (7) ◽  
pp. 072502 ◽  
Author(s):  
H. M. Smith ◽  
E. Verwichte
Keyword(s):  
Runaway Electron ◽  
Electron Generation

Suppression of runaway electron generation by massive helium injection after induced disruptions on TEXTOR

2015 ◽  
Vol 81 (5) ◽  
Author(s):  
A. Lvovskiy ◽  
H. R. Koslowski ◽  
L. Zeng ◽  
Keyword(s):  
Time Delay ◽  
Runaway Electron ◽  
Critical Density ◽  
Runaway Electrons ◽  
Electron Generation ◽  
Disruption Mitigation ◽  
Order Of Magnitude ◽  
Short Time ◽  
Short Time Delay

Disruptions with runaway electron generation have been deliberately induced by injection of argon using a disruption mitigation valve. A second disruption mitigation valve has been utilised to inject varying amounts of helium after a short time delay. No generation of runaway electrons has been observed when more than a critical amount of helium has been injected no later than 5 ms after the triggering of the first valve. The required amount of helium for suppression of runaway electron generation is up to one order of magnitude lower than the critical density according to Connor & Hastie (1975) and Rosenbluth & Putvinski (1997).

scholarly journals Kinetic modelling of runaway electron generation in argon-induced disruptions in ASDEX Upgrade

2020 ◽  
Vol 86 (4) ◽  
Author(s):  
K. Insulander Björk ◽  
G. Papp ◽  
O. Embreus ◽  
L. Hesslow ◽  
T. Fülöp ◽  
...  
Keyword(s):  
Runaway Electron ◽  
Kinetic Modelling ◽  
Electron Distribution Function ◽  
Real Space ◽  
Tokamak Plasmas ◽  
Runaway Electrons ◽  
Plateau Phase ◽  
Electron Generation ◽  
Current Dissipation ◽  
Threshold Amount

Massive material injection has been proposed as a way to mitigate the formation of a beam of relativistic runaway electrons that may result from a disruption in tokamak plasmas. In this paper we analyse runaway generation observed in eleven ASDEX Upgrade discharges where disruption was triggered using massive gas injection. We present numerical simulations in scenarios characteristic of on-axis plasma conditions, constrained by experimental observations, using a description of the runaway dynamics with a self-consistent electric field and temperature evolution in two-dimensional momentum space and zero-dimensional real space. We describe the evolution of the electron distribution function during the disruption, and show that the runaway seed generation is dominated by hot-tail in all of the simulated discharges. We reproduce the observed dependence of the current dissipation rate on the amount of injected argon during the runaway plateau phase. Our simulations also indicate that above a threshold amount of injected argon, the current density after the current quench depends strongly on the argon densities. This trend is not observed in the experiments, which suggests that effects not captured by zero-dimensional kinetic modelling – such as runaway seed transport – are also important.

Observation of two threshold fields for runaway-electron generation in tokamaks

2020 ◽  
Vol 60 (8) ◽  
pp. 084002
Author(s):  
X. Zhu ◽  
L. Zeng ◽  
Y. Liang ◽  
S. Lin ◽  
Y. Liu ◽  
...  
Keyword(s):  
Runaway Electron ◽  
Electron Generation

Runaway electron generation in a cooling plasma

2005 ◽  
Vol 12 (12) ◽  
pp. 122505 ◽  
Author(s):  
H. Smith ◽  
P. Helander ◽  
L.-G. Eriksson ◽  
T. Fülöp
Keyword(s):  
Runaway Electron ◽  
Electron Generation

scholarly journals Runaway electron generation in tokamak disruptions

2009 ◽  
Vol 51 (12) ◽  
pp. 124008 ◽  
Author(s):  
H M Smith ◽  
T Fehér ◽  
T Fülöp ◽  
K Gál ◽  
E Verwichte
Keyword(s):  
Runaway Electron ◽  
Electron Generation
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