Abstract
| Original language | English |
|---|---|
| Article number | 10D326 |
| Journal | Review of Scientific Instruments |
| Volume | 81 |
| Issue number | 10 |
| DOIs | |
| Publication status | Published - 2010 |
| MoE publication type | A1 Journal article-refereed |
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Keywords
- deuterium
- gold
- nickel
- plasma diagnostics
- plasma impurities
- plasma toroidal confinement
- plasma transport processes
- Tokamak devices
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The anomalous currents in the front foils of the JET lost alpha diagnostic KA-2. / Cecil, F.E.; Kiptily, V.; Salmi, Antti; Contributors, JET EFDA.
In: Review of Scientific Instruments, Vol. 81, No. 10, 10D326, 2010.Research output: Contribution to journal › Article › Scientific › peer-review
TY - JOUR
T1 - The anomalous currents in the front foils of the JET lost alpha diagnostic KA-2
AU - Cecil, F.E.
AU - Kiptily, V.
AU - Salmi, Antti
AU - Contributors, JET EFDA
PY - 2010
Y1 - 2010
N2 - We have examined the observed currents in the front foils of the JET Faraday cup lost alpha particle diagnostic KA-2. In particular, we have sought to understand the currents during Ohmic plasmas for which the ion flux at the detectors was initially assumed to be negligible. We have considered two sources of this current: plasma ions (both deuterium and impurity) in the vicinity of the detector (including charge exchange neutrals) and photoemission from scattered UV radiation. Based upon modeling and empirical observation, the latter source appears most likely and, moreover, seems to be applicable to the currents in the front foil during ELMy H-mode plasmas. A very thin gold or nickel foil attached to the present detector aperture is proposed as a solution to this problem, and realistic calculations of expected fluxes of lost energetic neutral beam ions during TF ripple experiments are presented as justification of this proposed solution.
AB - We have examined the observed currents in the front foils of the JET Faraday cup lost alpha particle diagnostic KA-2. In particular, we have sought to understand the currents during Ohmic plasmas for which the ion flux at the detectors was initially assumed to be negligible. We have considered two sources of this current: plasma ions (both deuterium and impurity) in the vicinity of the detector (including charge exchange neutrals) and photoemission from scattered UV radiation. Based upon modeling and empirical observation, the latter source appears most likely and, moreover, seems to be applicable to the currents in the front foil during ELMy H-mode plasmas. A very thin gold or nickel foil attached to the present detector aperture is proposed as a solution to this problem, and realistic calculations of expected fluxes of lost energetic neutral beam ions during TF ripple experiments are presented as justification of this proposed solution.
KW - deuterium
KW - gold
KW - nickel
KW - plasma diagnostics
KW - plasma impurities
KW - plasma toroidal confinement
KW - plasma transport processes
KW - Tokamak devices
U2 - 10.1063/1.3502040
DO - 10.1063/1.3502040
M3 - Article
VL - 81
JO - Review of Scientific Instruments
JF - Review of Scientific Instruments
SN - 0034-6748
IS - 10
M1 - 10D326
ER -