# Presentation: 814009

## FIRE Physics/Engineering Integration

- C. Kessel
- Princeton Plasma Physics Laboratory
- FIRE Project Meeting 11/7/2002

## Outline

- Reference H-mode Scenario
- Lower li from pedestals leads to higher coil currents
- Define operating range
- Advanced Tokamak Scenario
- Very low li from bootstrap and CD leads to higher coil currents
- Define operating range
**Plasma Control**
**Plasma Startup**
**RWM Coils**
**Power Handling and Limitations in AT plasmas**
**Other Analysis**
**Disruptions**
**Current Drive/Heating**
- Physics Validation Review
- Topical areas

## Plasma Control

- Vertical position control
- Determine peak I and V for random disturbance/drift and recover
- Use internal control coils
- Rely on magnetic measurements
- Radial position control (fast)
- Determine peak I and V for beta/li disturbances
- Use internal control coils
- Rely on magnetic and other (reflected power) measurements
- Plasma shape control (PFC standoff and strike points)
- Determine peak I and V for various disturbances
- Use all PF coils
- Rely on magnetic measurements
- Include a feedback feature to draw currents out of internal coils
- Plasma current control
- Determine peak I and V
- Use all PF coils
- Rely on magnetic measurements

## Plasma Startup

- Produce a loop voltage inside VV with PF coils, say 3-6 V
- Produce a field null, over as large a region as possible, say diameter of a/2
- Hold this configuration for a certain period, say 5 ms
- Utilize breakdown assistance like filament or EC, which allows lower voltages for breakdown
- Transition from field null to vertical field to hold plasma radially
- Rampup plasma current before feedback control begins, to say 100 kA
- FIRE has Cu cladding on SS vacuum vessel
- Inboard Cu cladding must be cut, any other ways to increase resistance
- Outboard Cu cladding probably doesn’t need to be cut
- Should make Cu tiles have short time constants

## RWM Coils --- DIII-D Experience

- Modes are detectable at the level of 1G
- The C-coils can produce about 50 times this field
- The necessary frequency depends on the wall time for the n=1 mode (which is 5 ms in DIII-D) and they have wall≈3
- FIRE has approximately 3-4 times the DIII-D plasma current, so we might be able to measure down to 3-4 G
- If we try to guarantee at least 10 times this value from the feedback coils, we must produce 30-40 G at the plasma
- These fields require approximately I = ZBr/o = 5-6.5 kA
- Assume we also require wall≈3
- Required voltage would go as V ≈ 3oRNI/wall
- Differences:
- DIII-D has coils outside the VV, far away, FIRE’s are very close
- DIII-D has 6 coils, FIRE has 8 with smaller toroidal extent
- DIII-D VV is made of Inconel, FIRE has Cu cladding on SS (wall)
- FIRE has large ports providing smaller wall area (VALEN model is accurate)

## Limitations for FIRE’s AT Operating Space -- Power Handling

- TF Coil Heating: Bt=10 T for 20s, Bt=8.5 T for 35 s ----> actually need Bt versus Pfusion with contours of constant t(flattop)
- Nuclear Heating in VV: (200 MW)  (20s) = 4000 MW-s ----> this virtually always sets t(flattop) limit
- Nuclear and Surface Heat Load on FW: < 1.0 MW/m2 with peaking factor of 2 ----> divide (Pbrem+Pline+Pcycl) by 60 m2 and multiply by 2.0
- Particle Heat Load to Divertor: P(SOL)-Pdiv(rad) < 28 MW ----> fraction of P(SOL) that is radiated in divertor is scanned and significantly enlarges operating space, assume all particle power goes to outboard legs
- Radiative Heat Load to Divertor and Baffle Surfaces: < 8 MW/m2 ----> Pdiv(rad) is multiplied by 0.8 and then divided by 14.5 m2 to get radiated heat flux on outboard divertor and baffle surfaces
- Divertor Coil Heating for low li Plasmas for Longest Pulses: Ip < 5.5 MA ----> this may become strongly limiting, especially if we lower Ipmax!!
- Installed Auxiliary/CD Power

## AT Operating Space in FIRE

## Other Analysis

- Disruption Analysis
- Need new layout for VV, etc.
- Produce fast vertical and fast radial disruptions
- Examine disruptions with plasma near midplane
- Include Cu cladding on SS VV
- Current Drive Analysis
- ICRF Ion heating by ORNL (full wave)
- LH in AT scenarios with LSC at PPPL and ACCOME by Bonoli at MIT
- Have CURRAY as stand alone code at PPPL and ORNL (full wave) for FW
- EC for NTM suppression, get a story together on this, simulation would require TORAY (simpler code for just heating??)