# Presentation: 802494

## Physics Analysis of FIRE

-  NSO PAC-3 Meeting
- July 10-11, 2001
- Madison, Wisconsin

**S. C. Jardin  **
**PPPL**
**with input from**
**C.Kessel, D.Meade, & the FIRE team**

## Outline

- Systems code scans over Aspect Ratio
- FIRE* operating point and reference discharge
- GLF23 Analysis
- Analysis of LHCD in FIRE
- Long Pulse Capability and AT modes
- Physics R & D Needs

## A Burning Plasma Systems Code (BPSC) has been developed for overall device optimization and evaluation

- Confinement (Elmy H-mode) ITER98(y,2):
- E = 0.144 I0.93 R1.39 a0.58 n200.41 B0.15 Ai0.19 0.78 P heat -0.69 H(y,2)
- Density Limit:           		n20 < 0.75 nGW = 0.75 IP/a2
- H-Mode Power Threshold:  	PLoss > (2.84/Ai) n200.58 B0.82 R a0.81
- MHD Stability:     		N =  / (IP/aB) < 1.8
- PAUX,  Q = PFUSION/PAUX, qCYL=                   _or_ qMHD,,  ZEFF  all held fixed
- Engineering Constraints:	1. Flux swing requirements in OH coil (V-S)
- 			2. Coil temperature not exceed 373o K
- 			3. Coil stresses remain within allowables
- Configuration Concept:  	1. OH coils _interior_ to TF coils, or
- 			2. OH coils _exterior_ to TF coils*
- 			3.  ST

## Scan over A, B, I shows FIRE* near optimum

## Dependence of Minimum R(A) on Confinement Factor H(y,2)

## Effect of Plasma Elongation varying with A

## Dependence of Device Size on Flattop Time

## Dependence of device size on plasma safety factor q

## Reduced size and cost options with T = 10, 5 s and/or  Q = 5

## A = 3.6

- 95 = 1.81
- PAUX = 15 MW
- qCYL = 2.2
- qMHD = 3.05
- E = 1.06 s
- P = 5.3 s
- TFLATTOP = 20 s
- J = 8.7 s
- fBS = 0.2
- fRAD = .41
- ZEFF = 1.4
- NWALL = 2 MW/m2

## TSC Simulation of Reference FIRE* Discharge with Burn Control

- Total Power

- alpha Power

- ICRF Power

- Ohmic Power

- Radiation

- P = 0.70	      ne = 5 1020	E = W/P =  800 ms = 0.8 H98(y,2)	         n= 1019
- T = 2.1%     Te0 = 11 keV          = W/(P-PRAD) = 1100 ms = 1.1 H98(y,2)        = 0.2%
- N = 1.6 %   W = 32 MJ         i (1)= 1.08      i (3)= 0.9

## Why a 20 sec discharge ?

- E ~ 1 sec  (energy confinement time)
- Other timescales of interest:
-   Current redistribution time ~ 10 s
-   Burn control time ~ 5-10 s
-   Helium Ash buildup time ~ 5-10
- These transient phenomena and others being studied with TSC

## TSC simulation of LHCD added to reference discharge shows it takes 10-20 sec to equilibrate

-   1.75 MA LHCD turned on at t=15 s
-   requires over 10 sec for current profile to adjust as seen by q=1 radius and li

## Comparison of 3 TSC FIRE simulations where P is changed suddenly at t=15 from 5E to 10E  or 50E 

- Comparison of 3 TSC FIRE simulations where P is changed suddenly at t=15 from 5E to 10E  or 50E

-  natural equilibration time for helium ash is 10-20 sec
-  note, shows the importance of particle control in divertor
-  Power required to keep stored energy at 40 MJ

## GLF23 Transport Model has been incorporated in TSC code and applied to FIRE*

-  Gives consistent result when applied to TFTR calibration shot 50911   (Te0 = 4 keV, Ti0 = 7 keV)
-  No rotation stabilization
-  Results depend strongly on (assumed) edge pedestal Temperature..need 2 keV
-  More optimistic than Kinsey’s UFA results.
- (4 keV for the old FIRE)
-  This is being investigated

## LHCD studies have been performed for FIRE* using JSOLVER and TSC/LSC

- r/a

- r/a

- total

- total

- BS

- BS

- LHCD

- q

- q

- J||

- J||

-  Radius of q=1 surface can be decreased by application of LHCD near edge

- _I(LHCD)_	_r/a(q=1)_
-    0.0	  0.425
-    1.0	  0.35
-    1.5	  0.30
-    2.0	  0.20
-    2.35	  0.10
-    2.55	  0.00

## LHCD for NTM Control in FIRE

- LSC lower hybrid calculation
- N|| = 2.5, N|| = 0.25
- PLH = 15 MW, ILH = 1.1 MA
- Need to examine:
- Narrower deposition
- Density and temperature dependence
- Reduction of power
- PEST-III evaluation of 

## Systems Code analysis of Long-Pulse AT FIRE* Discharges

## Possible upgrade to provide long pulse high-q capability at full field

- Plasma

- TF coil

- OH coil

- Proposed new center conductor to provide 2 T toroidal field for long pulse operation

- 28 s

- 21 s

- 40 s

- 40 s

- 50 s

- 50 s

- 38 s

- 51 s

- 51 s

- 51 s

- 51 s

- R

## Physics Areas Requiring Further Attention:

- _Physics Areas Requiring Further Attention:_
-  Disruption Physics: VDE, loads, runaway electrons, mitigation
-  Transport Modeling:  pedestal physics, ELMs, H-mode access
-  RF Physics:  Energy, current, rotation profiles: ICRH & LHCD
-  Energetic Particle Modes: map out stability boundaries, effects
-  Advanced Modes:  modeling and prototyping, RWM control
-  Error field correction coils: requirements, use for RWM
-  MHD physics:  1/1 mode, NTM stabilization , RWM, ELMs
-  Edge Physics:  UEDGE/DEGAS2 modeling, nsep / <ne>
-  AT modes: ITBs with low toroidal rotation, flat density, Te ~ Ti