Magnetics Program Highlights VLT Conference Call September 13, 2000

1
Magnetics Program HighlightsVLT Conference
CallSeptember 13, 2000

• presented by
• J.V. Minervini
• MIT Plasma Science and Fusion Center

2
Outline

• Summary of successful testing of CS Model Coil
  and CS Insert Coil
• Worlds largest pulsed superconducting and Nb3Sn
  magnet successfully tested
• Superconducting Quadrupole Magnets for IFE
• Progress made by LLNL and MIT in HCX prototype
  coil design and testing
• Successful acceptance test of LDX Floating Coil

3
CSMC is Composed of 3 Coil Modules


CS Insert Coil (JA)
US Inner Coil Module
JA Outer Coil Module

Schematic Assembly of CSMC and Support Structure
Coil Assembly in Test Facility
4
CSMC Was Extensively Tested

• I. CSMC test conditions
• A. DC operation
• 1. Confirmation of 13T at 4.5K and 5.3K
• 2. Critical properties determination
• 3. Joint resistance measurement
• B. AC loss measurement
• 1. Using resistive discharge at various
  currents and time constants
• 2. Using bi-polar field pulses
• 3. Using symmetric trapezoid field pulses
• C. Pulsed operation
• 1. Baseline scenarios to confirm 2K operating
  margin.
• 2. Determination of limiting ramp rates at T gt
  4.5K

5
CS Insert Was Extensively Tested

• II. CS Insert test conditions
• A. DC operation
• 1. Confirmation of 13T operation point
• 2. Determination of critical properties
  (normal and reverse current)
• B. AC loss measurement
• 1. With and without transport current in the
  insert
• 2. Using resistive discharge at various
  current levels and time constants
• 3. Using bi-polar field pulses
• 4. Using symmetric trapezoid field pulses
• C. Pulsed operation
• 1. Stability measurement using pulsed inductive
  heater
• 2. Confirm 2K operating margin
• 3. Determine limiting ramp rates at Tgt4.5K
• D. Quench propagation measurement
• E. Cyclic operation to 10,003 cycles

6
Results of DC Measurements
Initial analysis of current sharing temperature
shows conductor properties scale well from known
strand, temperature and strain data.
Joint Resistances were measured at 46 kA by
electrical and calorimetry methods.
7
Pulse Testing
13 T
0.6 T/s symmetric, trapezoidal ramp to 13T field
in the CS insert. Coil was ramped as fast as 2
T/S to 13T.
8
Ramp rate Limitation Tests
No anomalous Ramp Rate Limitation observed -
quenched by ?T due to AC Losses
9
Superconducting Properties Affected by Cycling
Decrease in Tcs of the CS Insert with number of
cycles. Effect needs to be further studied.
10
On Going Data Analyses
1. Conductor properties Incoloy magnetization,
further analysis of superconductors 2. Joint and
Conductor losses Joint losses consistent, ac
losses need signifcant analysis 3. Limiting ramp
rate limited by ac loss heating, HETR3D
simulation planned 4. Pulsed stability data
reduction continues, HETR3D simulations
planned 5. Quench propagation velocity, hot spot
temperature analysis 6. Coil properties mechanica
l, thermal analysis

• 2 Insert Coils Remain to be Tested in FY2001
• Nb3Sn TF-type conductor
• Nb3Al TF-type conductor

11
LLNL HCX quad schematic(Racetrack Coils)
Racetrack Quads for IFE Development Status at LLNL

• HCX LLNL prototype design complete
• Designed field quality works well in physics
  simulations
• Prototype fabrication is underway
• Winding and assembly trials, and tooling
  development is in progress
• Most of the parts for prototype program are
  procured
• Developed a conceptual design of the HCX
  assemblies with 6 quads in one with interfaces
  with other HCX systems

HCX layout
Focusing unit
Accelerating unit
12
Quadrupole Magnets for IFE Development Status at
MIT

• MIT is analysizing the Cos 2? mulitlayer coil
  designs of Advanced Magnet Lab. Inc. (AML)
• Magnetic field quality, stress analysis
• Manufacturing joints and lead arrangment
• Two single layer protoype HCX coils have been
  tested this summer at MIT
• Both coils showed premature quenching at joints
• New conductor and coil layer is being fabricated
  by AML
• MIT will test when ready this fall

3D model of HCX quad (one of four coils shown,
Cos2? spacing)
13
LDX Floating Coil Successfully Tested in July
F-Coil being inserted into MIT test dewar
Removing mandrel from F-Coil after completion of
final joint
Tested to 5.66T at 2200 amperes