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Magnetic Confinement of Cryogenic Plasma Produced by Pulsed Discharges in Superfluid Liquid Helium

Research Project

Project/Area Number 12680475
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field プラズマ理工学
Research InstitutionNiigata University

Principal Investigator

MINAMI Kazuo  Faculty of Engineering, Niigata University, Professor, 工学部, 教授 (00023135)

Project Period (FY) 2000 – 2001
Project Status Completed (Fiscal Year 2001)
Budget Amount *help
¥3,100,000 (Direct Cost: ¥3,100,000)
Fiscal Year 2001: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2000: ¥2,600,000 (Direct Cost: ¥2,600,000)
KeywordsLiquid Helium / Superconducting Coil / Pulsed Discharge / Stark Broadening / Magnetic Confinement / Mirror Field / Cusp Field / Needle Electrodes / 超伝導マグネット / 超流動 / 極低温 / プラズマ / 磁場閉じ込め / ミラー磁界 / カスプ磁界 / 磁気圧
Research Abstract

The effect of magnetic confinement has been investigated on the density decay of afterglow plasma produced by pulsed discharges between needle electrodes embedded in a split type superconducting coils with maximum magnetic field 2 T immersed in superfluid liquid helium (LHe). A pair of needle tungsten electrodes in mirror- or cusp-types magnetic field in LHe are fired by high voltage pulses of 20 kV, current 50 A, and time width 1.0μs. The Stark broadening of spectral line 587.6 nm from neutral helium atoms in plasma is observed to measure local plasma density. At time t=0.5μs after the discharge, the plasma density n=10^<18>cm^<-3>, and electron temperature Te=32,000 K. For a period until t=3.0μs after the dischagges, the estimated beta value defined by the ratio of plasma and magnetic pressures changes from 0.28 to 0.014. Effects of applied magnetic field are assumed to be evident. Somewhat surprisingly, no changes in density decays with and without magnetic field can be detected until t=3.0μs for both mirror- and cusp-type cases. We observe total light intensity until t=18 ms for detecting the difference. No differences with and without the magnetic field are detected. Reducing the pressure and temperature of LHe results in no difference.

Report

(3 results)
  • 2001 Annual Research Report   Final Research Report Summary
  • 2000 Annual Research Report
  • Research Products

    (2 results)

All Other

All Publications (2 results)

  • [Publications] E.Minami, Y.Yamanishi, C.Kojima, M.Shindo, O.Ishihara: "Very Slowly Decaying Afterglow Plasma in Cryogenic Helium Gas"IEEE Transactions Plasma Science. 31(印刷中). (2003)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2001 Final Research Report Summary
  • [Publications] K. Minami, Y. Yamanishi, C. Kojima, M. Shindo and O. Ishihara: "Very Slowly Decaying Afterglow Plasma in Cryogenic Helium Gas"IEEE Transactions Plasma Sciene. vol.31,no.3(in printing). (2003)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2001 Final Research Report Summary

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Published: 2000-04-01   Modified: 2016-04-21  

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