RF-Assisted Current Startup in the Fusion Engineering Device (FED)

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概要

• 論文の詳細を見る

• Auxiliary rf heating of electrons before and during the current rise phase in FED is examined as a means of reducing both the initiation loop voltage and resistive flux expenditure during startup. Prior to current initiation 1 to 2 MW of electron cyclotron resonance heating (ECRH) power at ∿90 GHz is used to create a small volume of high conductivity plasma (T_e ≃ 100eV, n_e ≃10^<13>cm^3) near the upper hybrid resonance (UHR) region. This plasma conditioning permits a small radius (a_o ≃0.2-0.4m) current channel to be established with a relatively low initial loop voltage (≲25 V). During the subsequent plasma expansion and current ramp phase, additional rf power is introduced to reduce volt-second consumption due to plasma resistance. A near classical particle and energy transport model has been developed to estimate the efficiency of electron heating in a currentless, toroidal plasma. The model assumes that MHD instabilities are absent due to the presence of an ambipolar sheath potential and a conducting limiter and vacuum vessel which "short-circuits" the vertical charge separation. Preferential electron heating at the UHR leads to the formation of an ambipolar electric field (E_<AMB>) at the conducting vessel and limiter, which introduces an effective rotational transform via poloidal E^^^→_<AMB>×B^^^→ drift. This drift improves particle confinement and enables the plasma to neutralize itself. The benefits of this effective electrostatic confinement are tempered; however, by the possibility of significant secondary electron emission from the limiters and vessel wall. Reasonable good agreement has been found between our theoretical estimates and the measurements made during ECR preheating experiments on the ISX-B tokamak. This agreement provides some confidence in the preheating power estimates obtained for the FED.

• 核融合科学研究所の論文

著者

• Peng Y-k.m.

  Fusion Engineering Design Center:oak Ridge National Laboratory Oak Ridge

• Peng Y-k.m.

  Fusion Engineering Design Center Oak Ridge National Laboratory Oak Ridge Tennessee U.s.a.

• BOROWSKI S.K.

  Fusion Engineering Design Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee, U.S.A.

• Kammash T.

  Fusion Engineering Design Center

• Kammash T.

  Fusion Engineering Design Center:oak Ridge National Laboratory Oak Ridge:university Of Michigan Ann

• Borowski S.k.

  Fusion Engineering Design Center:oak Ridge National Laboratory Oak Ridge:university Of Michigan Ann

• Borowski S.k.

  Fusion Engineering Design Center Oak Ridge National Laboratory Oak Ridge Tennessee U.s.a.

関連論文

• HIGH PERFORMANCE OPTIONS OF A FUSION ENGINEERING DEVICE (FED) WITH LOW q AND CURRENT DRIVE
• RF-Assisted Current Startup in the Fusion Engineering Device (FED)

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