. "RIV/61389021:_____/04:00103214" . "Gunn, J. P." . . . . "The Retarding Field Analyser (RFA) is essentially the only practical tool for the measurement of ion energies parallel to the total magnetic field in the tokamak scrape of layer plasma. One such device has recently been successfully employed at JET. Its bi-directional nature allows both measurements of ion temperature and plasma flow velocities. The latter are computed by collecting the ion saturation flux to negatively biased entrance slit plates which are set back inside a boron nitride protective housing. When comparing the RFA slit currents with those measured by a turbulent transport probe (TTP), the RFA fluxes are found to be a factor 4-5 lower for very similar plasma conditions. Using Particle-in-Cell (PIC) simulations, this contribution demonstrates unambiguously and quantitatively, that the RFA flux attenuation is induced by the magnetic pre-sheath formed in the orifice in front of the slit plates." . "C150;C156" . "Erents, S. K." . . . "[89AB8A6C21FC]" . "Czechoslovak Journal of Physics" . "578911" . "The Retarding Field Analyser (RFA) is essentially the only practical tool for the measurement of ion energies parallel to the total magnetic field in the tokamak scrape of layer plasma. One such device has recently been successfully employed at JET. Its bi-directional nature allows both measurements of ion temperature and plasma flow velocities. The latter are computed by collecting the ion saturation flux to negatively biased entrance slit plates which are set back inside a boron nitride protective housing. When comparing the RFA slit currents with those measured by a turbulent transport probe (TTP), the RFA fluxes are found to be a factor 4-5 lower for very similar plasma conditions. Using Particle-in-Cell (PIC) simulations, this contribution demonstrates unambiguously and quantitatively, that the RFA flux attenuation is induced by the magnetic pre-sheath formed in the orifice in front of the slit plates."@en . "retarding field analyser, magnetic pre-sheath, plasma flow, tunnel effect"@en . "Particle-in-cell simulations of the impact of retarding field analyser probe head geometry on ion saturation current measurements"@en . "US - Spojen\u00E9 st\u00E1ty americk\u00E9" . "54" . . "Particle-in-cell simulace vlivu tvaru hlavice sondy Retarding field analyz\u00E1toru na m\u011B\u0159en\u00ED iontov\u00E9ho nasycen\u00E9ho proudu"@cs . "7"^^ . . . "4"^^ . . "0011-4626" . "P\u00E1nek, Radom\u00EDr" . "Retarding Field Analyzer (RFA) je v podstat\u011B jedin\u00FD n\u00E1stroj na m\u011B\u0159en\u00ED energie iont\u016F ve sm\u011Bru magnetick\u00E9ho pole v okrajov\u00E9m plazmatu tokamaku. RFA byl ned\u00E1vno nainstalov\u00E1n v tokamaku JET a umo\u017E\u0148uje m\u011B\u0159en\u00ED iontov\u00E9 teploty a tak\u00E9 toku plazmatu. Ten je po\u010D\u00EDt\u00E1n z iontov\u00E9ho nasycen\u00E9ho proudu na z\u00E1porn\u011B nab\u00EDjen\u00E9 desky RFA um\u00EDst\u011Bn\u00E9 za tunelem v ochrann\u00E9m pouzdru sondy. Srovn\u00E1n\u00ED v\u00FDsledk\u016F m\u011B\u0159en\u00ED z RFA a sondy pro m\u011B\u0159en\u00ED turbulentn\u00EDho transportu (TTP) ukazuje, \u017Ee RFA m\u011B\u0159\u00ED 4-5 kr\u00E1t men\u0161\u00ED iontov\u00FD nasycen\u00FD proud. Pomoc\u00ED Particle-in-Cell simulac\u00ED ukazujeme v tomto p\u0159\u00EDsp\u011Bvku, \u017Ee zeslaben\u00ED toku plazmatu m\u011B\u0159en\u00E9ho pomoc\u00ED RFA je zp\u016Fsobeno vytvo\u0159en\u00EDm st\u011Bnov\u00E9 vrstvy v \u00FAst\u00ED tunelu hlavice."@cs . "P(GP202/03/P062), Z(AV0Z2043910)" . . "Particle-in-cell simulations of the impact of retarding field analyser probe head geometry on ion saturation current measurements" . "Pitts, R. A." . . . "1"^^ . . . "suppl.C" . "RIV/61389021:_____/04:00103214!RIV/2005/AV0/A52005/N" . "Particle-in-cell simulations of the impact of retarding field analyser probe head geometry on ion saturation current measurements" . "Particle-in-cell simulace vlivu tvaru hlavice sondy Retarding field analyz\u00E1toru na m\u011B\u0159en\u00ED iontov\u00E9ho nasycen\u00E9ho proudu"@cs . . . . "Particle-in-cell simulations of the impact of retarding field analyser probe head geometry on ion saturation current measurements"@en .