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8179115 
Journal Article 
A fast phosphor imaging diagnostic for two-dimensional plasma fluctuation measurements 
Liebscher, A; Luckhardt, SC; Antar, G; Zweben, S 
2001 
1 
Review of Scientific Instruments
ISSN: 0034-6748
EISSN: 1089-7623 
AMER INST PHYSICS 
MELVILLE 
72 
1 
953-956 
WOS:000166141600149 
A plasma imaging diagnostic is being developed using a fast time response ZnO:Zn phosphor disk to image plasma density fluctuations in a two-dimensional (2D) region. The plasma sensor consists of an 8.9 cm diameter phosphor coated aluminum disk that is inserted into the plasma and is excited by incident electrons resulting in a cathodoluminescent emission image. The phosphor light distribution is then interpreted as plasma density fluctuations using sheath theory and the phosphor response function. The local luminance S of fluctuating phosphor light is dependent on the incident electron energy E-e and current density through the equation S(r,t) = e integral R(E-e)(v.(n) over cap )f(e)(r,v,t)d(3)v, where R(E-e) is the energy dependent response function of the phosphor. The phosphor persistence time of 1-10 mus (emulsion dependent) combined with fast intensified charge coupled device camera shutter speeds enables the imaging of plasma fluctuations on microsecond range time scales. Broadband turbulent phosphor light fluctuations (f less than or equal to 500 kHz) have been measured with photodiode detectors and compared with Langmuir probe data. The 2D phosphor images show density profiles consistent with radial Langmuir probe measurements. Temporal and spatial resolution of the phosphor diagnostic enables 2D imaging of plasma turbulence and coherent modes. (C) 2001 American Institute of Physics. 
13th Topical Conference on High-Temperature Plasma diagnostics 
TUCSON, ARIZONA