Initial results from the lost alpha diagnostics on Joint European Torus

Abstract

Two devices have been installed in the Joint European Torus ͑JET͒ vacuum vessel near the plasma boundary to investigate the loss of energetic ions and fusion products in general and alpha particles in particular during the upcoming JET experiments. These devices are ͑i͒ a set of multichannel thin foil Faraday collectors and ͑ii͒ a well collimated scintillator, which is optically connected to a charge-coupled device. Initial results including the radial energy and poloidal dependence of lost ions from hydrogen and deuterium plasmas during the 2005-06 JET restart campaign will be presented.

Active Control of Type-I Edge-Localized Modes withn=1Perturbation Fields in the JET Tokamak

“…1. The traces are (a) the total input power, P tot , and the stored energy, W dia , (b) I EFCC , (c) the line-integrated electron densities, n e l, measured with an interferometer along two lines of sight, one close to the magnetic axis (upper trace) and the other near the pedestal top (lower trace), (d) the electron temperature, T e , from the ECE diagnostic measured near the center (upper trace) and at the pedestal top (lower trace), (e) the D signal measured at the outer divertor, (f) the fast ion loss current, I loss , measured by Faraday cups [15], and (g) a signal measured by a magnetic pickup coil. The pulse had a toroidal magnetic field of B t 1:84 T and a plasma current of I p 1:6 MA, corresponding to an edge safety factor of q 95 4:0.…”

Chapter 5: Burning Plasma Studies at JET

“…in mind but is sufficiently flexible to also see high-energy hydrogen and deuterium. 90 Its range of accessible pitch angles extends from 35 to 85 deg~5% resolution! ; detectable energies depend on the particle type since only particles with gyroradii between 30 and 140 mm~15% resolution!…”

Recent experimental results and modeling of RF heating of ([sup 3]He)-D JET plasmas: RF as a tool to study transport

“…A first assessment suggests 3 He tails of maximally 500keV were created. Both the number and the energy of lost fast ions [18] correlates with the RF power; the effect of the slowing down of the fast particles (fusion created protons) can clearly be observed on the lost ion time traces. As the RF heating was not tuned to H, these energetic protons likely arises from the D+ 3 He → 4 He(3.6MeV )+ p(14.7MeV ) reaction.…”