Download or read book High Harmonic Fast Wave Heating in NSTX written by B. P. LeBlanc and published by . This book was released on 2001 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Harmonic Fast Wave Heating Experiments on NSTX written by J. R. Wilson and published by . This book was released on 2000 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Results of High Harmonic Fast Wave Heating Experiments on NSTX written by J. Hosea and published by . This book was released on 2001 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High harmonic Fast wave Heating in NSTX written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: High-Harmonic Fast-Wave (HHFW), a radio-frequency technique scenario applicable to high-beta plasmas, has been selected as one of the main auxiliary heating systems on the National Spherical Torus Experiment (NSTX). The HHFW antenna assembly comprises 12 toroidally adjacent current elements, extending poloidally and centered on the equatorial plane. This paper reviews experimental results obtained with a symmetrical (vacuum) launching spectrum with k.
Download or read book Profile Modifications Resulting from Early High harmonic Fast Wave Heating in NSTX written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments have been performed in the National Spherical Torus Experiment (NSTX) to inject high harmonic fast wave (HHFW) power early during the plasma current ramp-up in an attempt to reduce the current penetration rate to raise the central safety factor during the flattop phase of the discharge. To date, up to 2 MW of HHFW power has been coupled to deuterium plasmas as early as t = 50 ms using the slowest interstrap phasing of k.
Download or read book Results of High Harmonic Fast Wave Heating Experiments on NSTX written by J. Hosea and published by . This book was released on 2001 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Harmonic Fast Wave Heating Experiments on NSTX written by J. R. Wilson and published by . This book was released on 2000 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Profile Modifications Resulting from Early High harmonic Fast Wave Heating in NSTX written by Jonathan Edward Menard and published by . This book was released on 2001 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High Harmonic Fast Wave Driven H mode Plasmas on NSTX written by R. E. Bell and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The launch of High-Harmonic Fast Waves (HHFW) routinely provides auxiliary power to NSTX plasmas, where it is used to heat electrons and pursue drive current. H-mode transitions have been observed in deuterium discharges, where only HHFW and ohmic heating, and no neutral beam injection (NBI), were applied to the plasma. The usual H-mode signatures are observed. A drop of the Da light marks the start of a stored energy increase, which can double the energy content. These H-mode plasmas also have the expected kinetic profile signatures with steep edge density and electron temperature pedestal. Similar to its NBI driven counterpart--also observed on NSTX-- the HHFW H mode have density profiles that features ''ears'' in the peripheral region. These plasmas are likely candidates for long pulse operation because of the combination of bootstrap current, associated with H-mode kinetic profiles, and active current drive, which can be generated with HHFW power.
Download or read book Recent Improvements in Fast Wave Heating in NSTX written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent improvements in high-harmonic fast wave (HHFW) core heating in NSTX are attributed to using lithium conditioning, and other wall conditioning techniques, to move the onset density for perpendicular fast wave propagation further from the antenna. This has resulted in the first observation of HHFW core electron heating in deuterium plasma at a launched toroidal wavenumber, k[phi] = -3 m-1, NSTX record core electron temperatures of 5 keV in helium and deuterium discharges and, for the first time, significant HHFW core electron heating of deuterium neutral-beam-fuelled H-mode plasmas. Also, k[phi] = -8 m-1 heating of the plasma startup and plasma current ramp-up has resulted in significant core electron heating, even at central electron densities as low as ~ 4x1018 m-3.
Download or read book Recent Fast Wave Coupling and Heating Studies on NSTX with Possible Implications for ITER written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Exploration of High Harmonic Fast Wave Heating on the National Spherical Torus Experiment written by J. R. Wilson and published by . This book was released on with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Edge Ion Heating by Launched High Harmonic Fast Waves in NSTX written by T. M. Biewer and published by . This book was released on 2004 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Recent Developments in High Harmonic Fast Wave Physics in NSTX written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the interaction between ion cyclotron range of frequency (ICRF) fast waves and the fast-ions created by neutral beam injection (NBI) is critical for future devices such as ITER, which rely on a combination ICRF and NBI. Experiments in NSTX which use 30 MHz High-Harmonic Fast-Wave (HHFW) ICRF and NBI heating show a competition between electron heating via Landau damping and transit-time magnetic pumping, and radio-frequency wave acceleration of NBI generated fast ions. Understanding and mitigating some of the power loss mechanisms outside the last closed flux surface (LCFS) has resulted in improved HHFW heating inside the LCFS. Nevertheless a significant fraction of the HHFW power is diverted away from the enclosed plasma. Part of this power is observed locally on the divertor. Experimental observations point toward the radio-frequency (RF) excitation of surface waves, which disperse wave power outside the LCFS, as a leading loss mechanism. Lithium coatings lower the density at the antenna, thereby moving the critical density for perpendicular fast-wave propagation away from the antenna and surrounding material surfaces. Visible and infrared imaging reveal flows of RF power along open field lines into the divertor region. In L-mode -- low average NBI power -- conditions, the fast-ion D-alpha (FIDA) diagnostic measures a near doubling and broadening of the density profile of the upper energetic level of the fast ions concurrent with the presence of HHFW power launched with k// =-8m-1. We are able to heat NBI-induced H-mode plasmas with HHFW. The captured power is expected to be split between absorption by the electrons and absorption by the fast ions, based on TORIC calculation. In the case discussed here the Te increases over the whole profile when ~2MW of HHFW power with antenna k// =13m-1 is applied after the H-mode transition. But somewhat unexpectedly fast-ion diagnostics do not observe a change between the HHFW heated NBI discharge and the reference NBI only plasma, although an increase in neutron production is measured. __________________________________________________
Download or read book High harmonic Fast Wave Heating and Current Drive Results for Deuterium H mode Plasmas in the National Spherical Torus Experiment written by and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A critical research goal for the spherical torus (ST) program is to initiate, ramp-up, and sustain a discharge without using the central solenoid. Simulations of non-solenoidal plasma scenarios in the National Spherical Torus Experiment (NSTX) [1] predict that high-harmonic fast wave (HHFW) heating and current drive (CD) [2] can play an important roll in enabling fully non-inductive (fNI ≈ 1) ST operation. The NSTX fNI ≈ 1 strategy requires 5-6 MW of HHFW power (PRF) to be coupled into a non-inductively generated discharge [3] with a plasma current, Ip ≈ 250-350 kA, driving the plasma into an HHFW H-mode with Ip ≈ 500 kA, a level where 90 keV deuterium neutral beam injection (NBI) can heat the plasma and provide additional CD. The initial approach on NSTX has been to heat Ip ≈ 300 kA, inductively heated, deuterium plasmas with CD phased HHFW power [2], in order to drive the plasma into an H-mode with fNI ≈ 1.
Download or read book Investigation of Ion Absorption of the High Harmonic Fast Wave in NSTX Using HPRT written by Adam Lewis Rosenberg and published by . This book was released on 2001 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Edge Ion Heating by Launched High Harmonic Fast Waves in NSTX written by T. M. Biewer and published by . This book was released on 2004 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:
