A high density Field Reversed Configuration plasma target for Magnetized Target Fusion: First internal profile measurements
Abstract
Los Alamos National Laboratory leads a program to demonstrate the scientific basis of Magnetized Target Fusion (MTF). MTF is a potentially low cost path to fusion intermediate in plasma regime between magnetic and inertial fusion energy, requiring compression of a magnetized target plasma and PdV heating to fusion relevant conditions inside a converging flux conserver. We have chosen a Field Reversed Configuration (FRC) target plasma compressed within an imploding metal liner. FRX-L (FRC-Liner) experimental data with high density (2-5x10^22m-3), temperature (T ≈ 200-400eV), and configuration lifetime (τN ≈ 8-12 μ sec) are within a factor of 2-3 of that required for a full performance MTF target. To reduce losses of initial bias magnetic flux during FRC formation, we are improving our formation strategy to trap and retain magnetic flux, so that its dissipation can heat particles. Internal plasma profile measurements enhance our understanding of the physics basis of the magnetic and particle partition of energy, and guide experimental tactics. The Lundquist number is 2000-10000, while ion-ion collisionality remains significant for this dense FRC. Anomalous resistivity presumably mediates flux dissipation at the field null resulting in plasma heating and possibly plasma flow. Resistivity at the O-point and at the separatrix radius may be inferred from radial gradients of the magnetic field and flux decay rate. Radial pressure balance relates plasma pressure to the local magnetic field, so resistivity depends on β (r) profiles, which we determine with interferometery and Thomson scattering. We summarize four years of technical and physics progress, and identify the near term path to optimize the FRC formation for later injection into a liner.
- Publication:
-
APS Division of Plasma Physics Meeting Abstracts
- Pub Date:
- October 2003
- Bibcode:
- 2003APS..DPPCI2003I