# Presentation: 114739

## Physics Basis of FIRE Next Step Burning Plasma Experiment

- Charles Kessel
- Princeton Plasma Physics Laboratory
- U.S.-Japan Workshop on Fusion Power Plant Design, University of Tokyo
- March 29-31, 2001

- http://fire.pppl.gov

## Goals of the FIRE Study

- Using the high field compact tokamak, produce burning plasmas with Q > 5-10 over pulse lengths > 2 current diffusion times, to study and resolve both standard and advanced tokamak burning plasma physics issues, for $1B

## Slide 3

## Slide 4

## FIRE Has Many Features Similar to ARIES Tokamaks

## FIRE Looks Like a Scale Model of ARIES-AT

- Nw = 3 MW/m2
- Pfus = 12 MW/m3

- Nw = 3.3 MW/m2
- Pfus = 5.3 MW/m3

## FIRE Can Access Various Pulse Lengths by Varying BT

## FIRE’s Divertor Must Handle Attached(25 MW/m2) and Detached(5 MW/m2) Operation

## FIRE’s Divertor is Designed to Withstand Large Eddy Current and Halo Current Forces

## FIRE Must Handle Disruptions

- VDE Simulation with 3 MA/ms Current Quench

## FIRE Has Several Operating Modes Based on Present Day Physics

- Reference: ELMing H-mode
- B=10 T, Ip=6.5 MA, Q=5, t(pulse)=18.5 s
- High Field: ELMing H-mode
- B=12 T, Ip=7.7 MA, Q=10, t(pulse)=12 s

- AT Mode: Reverse Shear with fbs>50%
- B=8.5 T, Ip=5.0 MA, Q=5, t(pulse)=35 s
- Long Pulse DD: AT Mode and H-mode
- B=4 T, Ip=2.0 MA, Q=0, t(pulse)>200 s

- FIRE can study both burning AND long pulse plasma physics in the same device

## Progress Toward ARIES-like Plasmas Requires A Series of Steps

- 1) stabilize NTM’s
- 2) stabilize n=1 RWM
- 3) stabilize n>1 RWMs
- *each step with higher fbs
- **each step with more profile control

## FIRE is Examining Ways to Feedback Control RWM/Kink Modes

## FIRE Must Satisfy Present Day Physics Constraints

## FIRE Can Access Most of the Existing H-mode Database

## FIRE’s Performance With Projected Confinement

## FIRE Is Being Designed to Access Higher  AT Plasmas

## Slide 18

## Plasma Response to Paux Modulation

- Plasma Response to Paux Modulation

## Plasma Response to Fueling Modulation

## Divertor Pumping Strongly Affects Plasma Burn

## TSC Simulation of FIRE Burning AT Discharge

- Ip=5 MA, Bt=8.5 T, N=3.0, li(3)=0.4, n/nGr=0.7, H(y,2)=1.15, PLH=20 MW, PICRF=18 MW, n(0)/<n>=1.45

## TSC Simulation of FIRE Burning AT Discharge

## A Burning Device Like FIRE Must Validate Assumptions Made in Power Plant Studies Like ARIES

- Power and particle handling in the divertor/SOL/first wall
- Stabilization of NTM’s
- Stabilization of RWM/Kink modes
- Large bootstrap fraction plasmas with external CD

- Control of current, n, and T profiles
- Develop methods to mitigate/avoid disruptions
- Demonstrate energetic particle effects are benign
- All in a plasma with significant alpha particle heating

## The FIRE Design is Evolving

- What can the machine do?
- Q
- Pulse length
- T and n variations
- Heating/fueling/pumping/current drive
- What is the impact of physics uncertainties?
- Scaling of E
- Scaling of Pth(L to H)

- NTM -limit
- Density limit
- Particle confinement p*/E
- What is machine flexibility to examine physics issues?
- Burn control
- AE, energetic particles
- Sawteeth, other MHD
- AT profile interactions (p(r), j(r), (r))