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A 100 KW Class Applied-field Magnetoplasmadynamic Thruster
11:47

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Published on: December 22, 2018

Tokamak startup using point-source dc helicity injection.

D J Battaglia1, M W Bongard, R J Fonck

  • 1Department of Engineering Physics, University of Wisconsin, 1500 Engineering Drive, Madison, Wisconsin 53706, USA.

Physical Review Letters
|August 8, 2009
PubMed
Summary
This summary is machine-generated.

Startup of a tokamak plasma was achieved on the Pegasus Toroidal Experiment using localized current sources. The plasma current is sustained by magnetic turbulence and helicity balance, forming a tokamak-like magnetic topology.

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Area of Science:

  • Plasma Physics
  • Fusion Energy Research
  • Magnetic Confinement Fusion

Background:

  • Tokamak devices are crucial for magnetic confinement fusion energy research.
  • Achieving stable plasma startup and sustainment is a key challenge in fusion devices.
  • Ultralow aspect ratio tokamaks offer potential advantages in plasma confinement and stability.

Purpose of the Study:

  • To demonstrate the startup of a tokamak plasma on the Pegasus Toroidal Experiment.
  • To investigate the role of localized current sources in plasma formation.
  • To understand the mechanisms governing plasma current sustainment and magnetic topology formation.

Main Methods:

  • Utilizing three localized, high-current density sources mounted near the outboard midplane.
  • Injecting open field current into the experimental device.
  • Analyzing plasma behavior through magnetic turbulence and helicity balance.

Main Results:

  • Successful startup of a 0.1 MA tokamak plasma was achieved.
  • The injected current relaxed into a tokamak-like magnetic topology.
  • Plasma current sustainment was linked to helicity balance and magnetic relaxation.

Conclusions:

  • Localized current injection is an effective method for tokamak plasma startup.
  • Helicity-conserving magnetic turbulence plays a vital role in forming and sustaining tokamak magnetic topology.
  • Plasma current limits are governed by helicity balance and magnetic relaxation dynamics.