Exploring the regime of validity of global gyrokinetic simulations with spherical tokamak plasmas
- Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Univ. of Wisconsin, Madison, WI (United States)
- Univ. of California, Davis, CA (United States)
- Nova Photonics, Inc., Princeton, NJ (United States)
Plasma turbulence is considered one of the main mechanisms for driving anomalous thermal transport in magnetic confinement fusion devices. Based on first-principle model, gradient driven gyrokinetic simulations have often been used to explain turbulence-driven transport in present fusion devices, and in fact, many present predictive codes are based on the assumption that turbulence is gradient-driven. However, using the electrostatic global particle-in-cell gyrokinetic tokamak simulation (GTS) code (Wang et al 2010 Phys. Plasmas 17 072511), we will show that while global gradient-driven gyrokinetic simulations provide decent agreement in ion thermal transport with a set of NBI-heated NSTX (Ono et al 2000 Nucl. Fusion 40 557) H-mode plasmas, they are not able to explain the observed electron thermal transport variation in a set of RF-heated L-mode plasmas, where a factor of 2 decrease in electron heat flux is observed after the cessation of the RF heating. Thus, identifying the regime of validity of the gradient-driven assumption is essential for first-principle gyrokinetic simulation. This understanding will help us to more confidently predict the confinement performance of ITER and future magnetic confinement devices.
- Research Organization:
- Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States); Univ. of California, Davis, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES)
- Grant/Contract Number:
- AC02-09CH11466; AC02-76CH03073; FG03-95ER54295; FG03-99ER54518; FG02-99ER54518
- OSTI ID:
- 1616946
- Alternate ID(s):
- OSTI ID: 1777994
- Journal Information:
- Nuclear Fusion, Vol. 60, Issue 2; ISSN 0029-5515
- Publisher:
- IOP ScienceCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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