Simulations towards the achievement of non-inductive current ramp-up and sustainment in the National Spherical Torus Experiment Upgrade

Poli, F. M.; Andre, R. G.; Bertelli, N.; Gerhardt, S. P.; Mueller, D.; Taylor, G.

doi:10.1088/0029-5515/55/12/123011

Title: Simulations towards the achievement of non-inductive current ramp-up and sustainment in the National Spherical Torus Experiment Upgrade

Journal Article · Fri Oct 30 00:00:00 EDT 2015 · Nuclear Fusion

DOI:https://doi.org/10.1088/0029-5515/55/12/123011· OSTI ID:1256702

^[1]; Andre, R. G. ^[1]; Bertelli, N. ^[1]; Gerhardt, S. P. ^[1];

^[1]; Taylor, G. ^[1]

Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

One of the goals of the National Spherical Torus Experiment Upgrade (NSTX-U) (Menard et al 2012 Nucl. Fusion 52 083015) is the demonstration of fully non-inductive start-up, current ramp-up and sustainment. This work discusses predictive simulations where the available heating and current drive systems are combined to maximize the non-inductive current and minimize the solenoidal contribution. Radio-frequency waves at harmonics higher than the ion cyclotron resonance (high-harmonic fast waves (HHFW)) and neutral beam injection are used to ramp the plasma current non-inductively starting from an initial Ohmic plasma. An interesting synergy is observed in the simulations between the HHFW and electron cyclotron (EC) wave heating. Furthermore, time-dependent simulations indicate that, depending on the phasing of the HHFW antenna, EC wave heating can significantly increase the effectiveness of the radio-frequency power, by heating the electrons and increasing the current drive efficiency, thus relaxing the requirements on the level of HHFW power that needs to be absorbed in the core plasma to drive the same amount of fast-wave current.

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Research Organization:: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Grant/Contract Number:: AC02-CH0911466

OSTI ID:: 1256702

Alternate ID(s):: OSTI ID: 1238877

Report Number(s):: PPPL-5125

Journal Information:: Nuclear Fusion, Vol. 55, Issue 12; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

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Cited by: 14 works

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Title: Simulations towards the achievement of non-inductive current ramp-up and sustainment in the National Spherical Torus Experiment Upgrade

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