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Title: High fusion performance at high Ti/Te in JET-ILW baseline plasmas with high NBI heating power and low gas puffing

Journal Article · · Nuclear Fusion
 [1];  [2];  [3];  [3];  [3]; ORCiD logo [3];  [4];  [3];  [5];  [5]
  1. Culham Science Centre, Abingdon (United Kingdom). EUROfusion Programme Management Unit
  2. Culham Science Centre, Abingdon (United Kingdom). JET Exploitation Unit
  3. Culham Science Centre, Abingdon (United Kingdom). Culham Centre for Fusion Energy (CCFE)
  4. Culham Science Centre, Abingdon (United Kingdom). Culham Centre for Fusion Energy (CCFE); Lab. for Plasma Physics of the Ecole Royale Militaire / Koninklijke Militaire School (LPP-ERM/KMS), Brussels (Belgium)
  5. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)

This article presents the transport analysis of high density baseline discharges in the 2016 experimental campaign of the Joint European Torus with the ITER-Like Wall (JET-ILW), where a significant increase in the deuterium–deuterium (D–D) fusion neutron rate (~2.8 × 1016 s-1) was achieved with stable high neutral beam injection (NBI) powers of up to 28 MW and low gas puffing. Increase in Ti exceeding Te were produced for the first time in baseline discharges despite the high electron density; this enabled a significant increase in the thermal fusion reaction rate. As a result, the new achieved record in fusion performance was much higher than the previous record in the same heating power baseline discharges, where Ti = Te. In addition to the decreases in collisionality and the increases in ion heating fraction in the discharges with high NBI power, Ti > Te can also be attributed to positive feedback between the high Ti/Te ratio and stabilisation of the turbulent heat flux resulting from the ion temperature gradient driven mode. The high Ti/Te ratio was correlated with high rotation frequency. Among the discharges with identical beam heating power, higher rotation frequencies were observed when particle fuelling was provided by low gas puffing and pellet injection. Lastly, this reveals that particle fuelling played a key role for achieving high Ti/Te, and the improved fusion performance.

Research Organization:
Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
Sponsoring Organization:
USDOE; European Commission (EC)
Contributing Organization:
JET contributors
Grant/Contract Number:
633053
OSTI ID:
1432663
Journal Information:
Nuclear Fusion, Vol. 58, Issue 3; ISSN 0029-5515
Publisher:
IOP ScienceCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 25 works
Citation information provided by
Web of Science

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  • Chapman, I. T.; Morris, A. W.
  • Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 377, Issue 2141 https://doi.org/10.1098/rsta.2017.0436
journal February 2019
Global scaling of the heat transport in fusion plasmas journal January 2020
Global scaling of the heat transport in fusion plasmas text January 2019
New plasma regimes with small ELMs and high confinement at the Joint European Torus text January 2021

Figures / Tables (10)