XP-425: HHFW H-mode Plasma Development

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XP-425 HHFW H-mode Plasma Development

• B.P. LeBlanc
• NSTX Meeting
• 17-May-2004

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HHFW H Mode Reproduced
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Many Goals Achieved

• Develop a dependable DND HHFW H-mode plasma
• Separate plasma fueling from antenna coupling
• CS gas injector and/or DND geometry
• Expand operational envelope
• Ip 0.3-0.5 MA, BT 0.37 - 0.45 T, low density,
  LSN
• k// 14 m-1
• New range achieved
• Ip 0.6-0.8 MA, BT 0.45 T, medium density DND
• k// 14 and 7 m-1
• Document HHFW H-mode plasma
• Many discharges with beam blips
• ERD was on

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k// 14 m-1, 1.5 MW
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NB Blips Add ?10 to WMHD
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Fast Particles Accelerated by WaveNeutron trace
peaks after NB blip turnoff
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Source C 10-ms blips for CHERSPreliminary CHERS
analysis
Ti Te for r/a lt 0.5 Te gt Ti in core vtor lt 10
km/s
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Data Set of 20 April 2004

• 25 discharges
• 12 with beam blips
• 12 with k// 14/m
• 12 with k// 7/m
• 1 without RF
• 14 with Ip 0.6 MA
• 10 with Ip 0.7 MA
• 1 with Ip 0.8 MA
• 17 with H-mode

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Next Step

• Document HHFW H-mode plasmas with Prf ? 3 MW for
  k// 7 and 14 m-1
• Investigate Ip 0.8 MA
• Provide HHFW driven H-mode plasmas suitable for
  NBI heating
• Reduce beam blip energy input
• Lower beam energy to 75 keV
• Turn off beam during CHERS readout time