Shawn Tang

Resonant Pitch-Angle Scattering Of Runaway-Electrons by Externally-launched Helicon Waves in the DIII-D Tokamak

Hari Choudhury, Jeff Lestz, Carlos Paz-Soldán, A. Battey et autres

Resonant wave-particle interactions between externally launched helicon waves (also known as whistler waves) and runaway electrons (REs) have been demonstrated on the DIII-D tokamak. In this work we extend the initial results reported in Choudhury, H. et al. Phys. Rev. Lett. 136, …

Resonant Pitch-Angle Scattering Of Runaway-Electrons by Externally-launched Helicon Waves in the DIII-D Tokamak

Hari Choudhury, Jeff Lestz, Carlos Paz-Soldán, A. Battey et autres

Resonant wave-particle interactions between externally launched helicon waves (also known as whistler waves) and runaway electrons (REs) have been demonstrated on the DIII-D tokamak. In this work we extend the initial results reported in Choudhury, H. et al. Phys. Rev. Lett. 136, …

us, ch (code pays fourni par la source)

The Thales TH1512: A New 117.5 GHz 1 MW Continuous-Wave Industrial Gyrotron for the DIII-D Tokamak

Alberto Leggieri, Konstantinos A. Avramidis, Nikolai de Boucaud, Loannis Chelis et autres

This paper presents the design, fabrication and preliminary assessment of the THALES TH1512 1 MW 117.5 GHz CW gyrotron, dedicated to the DIII-D fusion facility. Short pulse tests at KIT demonstrated 1.3 MW output and $48\%$ efficiency with readiness for long-pulse operation.

gr, us, de (code pays fourni par la source)

Dependence of ion-cyclotron range of frequencies instabilities on species mix and fast-ion distribution: II. Time evolution

William W. Heidbrink, Genevieve DeGrandchamp, Jeff Lestz, Kathreen E. Thome et autres

Abstract Dedicated DIII-D experiments studied instabilities below the ion cyclotron frequency f ci and at cyclotron harmonics by injecting thirteen different neutral beam populations into plasmas with different thermal compositions of H and D at five different values of toroidal field. The …

us (code pays fourni par la source)

Real-time steerable frequency-stepped Doppler backscattering (DBS) system for local helicon wave electric field measurements on the DIII-D tokamak

Satyajit Chowdhury, N. A. Crocker, W. A. Peebles, R. Lantsov et autres

A new frequency-stepped Doppler backscattering (DBS) system has been integrated into a real-time steerable electron cyclotron heating launcher system to simultaneously probe local background turbulence (f < 10 MHz) and high-frequency (20-550 MHz) density fluctuations in the DIII-D tokamak. The launcher allows …

us (code pays fourni par la source)

Real-time steerable frequency-stepped Doppler Backscattering (DBS) System for local helicon wave electric field measurements on the DIII-D tokamak

Satyajit Chowdhury, N. A. Crocker, W. A. Peebles, R. Lantsov et autres

A new frequency-stepped Doppler backscattering (DBS) system has been integrated with a real-time steerable electron cyclotron heating launcher to probe local background turbulence (f<10 MHz) and high-frequency (20-550 MHz) density fluctuations in the DIII-D tokamak. The launcher enables 2D steering (horizontal and …

First high-power helicon results from DIII-D

Robert I. Pinsker, B. Van Compernolle, Shawn Tang, Jeff Lestz et autres

Abstract More than 0.6 MW of rf power at 476 MHz has been coupled to DIII-D plasmas by launching helicon (whistler) waves with a traveling-wave antenna (comb-line) in the fast-wave polarization (Van Compernolle et al 2021 Nucl. Fusion 61 116034) which resulted …

us (code pays fourni par la source)

Parametric decay instabilities driven by high power helicon waves in DIII-D

Miklos Porkolab, Robert I. Pinsker, Genevieve DeGrandchamp, S. G. Baek et autres

High power helicon waves (whistler or very high harmonic fast lower hybrid waves) at a frequency of 476 MHz are being tested for efficient off-axis current drive on DIII-D with the goal of demonstrating profile control in AT plasmas [1-4]. In agreement …

Stabilization of Alfvén Eigenmodes in DIII-D via Controlled Energetic Ion Density Ramp and Validation of Theory and Simulations

Shawn Tang, Troy A. Carter, N. A. Crocker, William W. Heidbrink et autres

Fast-ion driven Alfvén waves with frequency close to the ion cyclotron frequency (f=0.58f_{ci}) excited by energetic ions from a neutral beam are stabilized via a controlled energetic ion density ramp for the first time in a fusion research plasma. The scaling of …

us (code pays fourni par la source)

Stabilization of Alfv\'{e}n Eigenmodes in DIII-D via Controlled Energetic Ion Density Ramp and Validation of Theory and Simulations

Shawn Tang

Global Alfven eigenmode (GAE) simulations for NSTX(-U) and DIII-D

Elena V. Belova, N. A. Crocker, Shawn Tang, Jeff Lestz et autres

Species mix, magnetic field strength, and distribution function dependence of instabilities near the ion cyclotron range of frequencies

Genevieve DeGrandchamp, William W. Heidbrink, Kathreen E. Thome, M. A. Van Zeeland et autres