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1 CAE stochastic heating

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Early theoretical history '75 Smith&Kaufman proposed stochastic ion heating by ... Data on coupling to beam-excited modes will be acquired in piggyback fashion ... – PowerPoint PPT presentation

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Title: 1 CAE stochastic heating


1
1) CAE stochastic heating
  • Goal is direct heating of thermal ions with low
    frequency ( 1 MHz) RF system
  • Stochastic ion heating with large amplitude
    waves has been demonstrated in small experiment
  • Observed CAE/GAE spectrum suggest many modes
    available to couple to, and relatively low power
    threshold to excite measurable modes.
  • Estimated power required (a few kW to create
    observed mode amplitude?)
  • ?pol/2 over RF antenna from Mirnov array
  • Approximately 10 times more power to reach
    stochastic threshold below stochastic threshold,
    damping is primarily on electrons.
  • Early theoretical history
  • '75 SmithKaufman proposed stochastic ion heating
    by oblique ES wave
  • '77 KarneyBers, stochastic ion heating by
    perpendicular ES wave
  • '78 Karney, ion heating in lower hybrid wave
  • '79 Hsu,Matsuda,ChuJensen, parallel standing
    wave
  • '81 DrakeLee, Lower hybrid drift wave and
    multiple waves
  • Experimental documentation of stochastic thermal
    ion heating
  • '87'91 McChesney,SternBellan, stochastic ion
    heating with drift-Alfvén wave
  • '9395 Bailey,BellanStern, thermal-ion
    equilibrium distributions
  • '98 Sanders,BellanStern, transport effects on
    distribution function

2
CAE stochastic ion heating
  • Experiment goals
  • Document coupling of RF antenna strap to
    NBI-excited CAE.
  • Measure antenna loading in AE quiescent regime
    (possibly ohmic shot, maybe with AE present)
  • Run plan and run time
  • Perform antenna modifications for last week of
    operation
  • Data on coupling to beam-excited modes will be
    acquired in piggyback fashion
  • There should be a spare channel in the HF data
    acquisition system.
  • Need to run cable to RF antenna, install voltage
    divider/matching network.
  • If things are going well, measure antenna loading
    with low power source?
  • Results will help prepare for more extensive
    experiments next year.

3
Excitation of AE by ICRF beat wave excitation
  • Feasibility demonstrated on JET by Fasoli, et.
    al. (NF 36 258) with H-minority heating
  • Origin of non-linearity could be wave-wave
    physics or antenna-plasma coupling
  • Provides direct measure of mode damping rate -
    potentially for CAE/GAE as well as TAE modes.
  • Potential piggy-back XP?
  • May need high power for non-linear physics.
  • Need reference signal, may need ability to scan
    beat frequency?
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