title: Near midplane scintillator-based fast ion loss detector on DIII-D.
abstract: A new scintillator-based fast-ion loss detector (FILD) installed near the outer midplane of the plasma has been commissioned on DIII-D. This detector successfully measures coherent fast ion losses produced by fast-ion driven instabilities (≤500 kHz). Combined with the first FILD at ∼45° below the outer midplane [R. K. Fisher, et al., Rev. Sci. Instrum. 81, 10D307 (2010)], the two-detector system measures poloidal variation of losses. The phase space sensitivity of the new detector (gyroradius r(L) ∼ [1.5-8] cm and pitch angle α ∼ [35°-85°]) is calibrated using neutral beam first orbit loss measurements. Since fast ion losses are localized poloidally, having two FILDs at different poloidal locations allows for the study of losses over a wider range of plasma shapes and types of loss orbits.
authors.affiliation: University of California-Irvine, USA. chenxi@fusion.gat.com
authors.forename: X
authors.initials: X
authors.lastname: Chen
authors.forename: R K
authors.initials: RK
authors.lastname: Fisher
authors.forename: D C
authors.initials: DC
authors.lastname: Pace
authors.forename: M
authors.initials: M
authors.lastname: García-Muñoz
authors.forename: J A
authors.initials: JA
authors.lastname: Chavez
authors.forename: W W
authors.initials: WW
authors.lastname: Heidbrink
authors.forename: M A
authors.initials: MA
authors.lastname: Van Zeeland