# Presentation: 511301

## Advanced Tokamak Modes in FIRE

**Advanced Tokamak Modes in FIRE**

**ITPA MHD Task Group Meeting**
**St. Petersburg, Russia**
**July 15, 2003**

***AES, ANL, Boeing, Columbia U., CTD, GA, GIT, LLNL, INEEL,***
*** ******MIT, ORNL, PPPL, SNL, SRS, UCLA, UCSD, UIIC, UWisc,****** ***

***FIRE Collaboration***

***http://fire.pppl.gov***

**Dale Meade, Charles Kessel and Steve Jardin**

## Fusion Ignition Research Experiment  (FIRE)

**Fusion Ignition Research Experiment  (FIRE)**

-  **R = 2.14 m,  a = 0.595 m**
** ****B = 10 T,      (~ 6.5 T, AT)**
** ****I****p****  = 7.7 MA, (~ 5 MA, AT)**
** ****P****ICRF**** = 20 MW**
** ****P****LHCD**** ≤ 30 MW (Upgrade)**
** ****P****fusion**** ~ 150 MW**
** ****Q ≈ 10,          (5, AT)**
** ****Burn time ≈ 20s (2 ********CR****-Hmode)**
**      ≈ ****40s (< 5 ********CR****-AT)**
** ****Tokamak Cost = $350M (FY02)**
** ****Total Project Cost = $1.2B (FY02)**

**1,400 tonne**

**Mission: to attain, explore, understand and optimize magnetically-confined fusion-dominated plasmas**

## Characteristics of FIRE

**Characteristics of FIRE**

-  40% scale of ARIES plasma xsection
-  x = 2.0, x = 0.7, ripple ≈ 0.3%
-  All metal PFCs
-  Actively cooled W divertor
-  Be tile FW, cooled between shots
-  T inventory ~ TFTR
-  Close Fitting Copper Stabilizers
-  Position control coils btwn VV shells
-  RWM coils in the first wall
-  75 -115 MHz ICRF for heating and on-axis CB, ~5 GHz LH for  off-axis CD, 170 GHz ECCD for NTM stabilization

## Slide 4

## FIRE Plasma Regimes

**Operating Modes**
- •  Elmy H-Mode
- •  Improved H-Mode
- •  Reversed Shear AT
- 	-  OH assisted
- 	**- “steady-state”**
**	****    ****(100% NI)**

- 	**H-Mode**	**AT(ss)****	****ARIES-RS/AT**
- R/a	   3.6	 3.6		    4
- B (T) 	  10 	 6.5  	 	  8 - 6
- Ip  (MA) 	  7.7 	 5 		12.3-11.3
- n/nG	   0.7	0.85		1.7-0.85
- H(y,2)	  1.1	1.2 – 1.7		0.9 - 1.4
- N	  1.8	≤ 4.2		4.8 - 5.4
- fbs ,%	  25	 77		88 - 91
- Burn/CR	   2	 3 - 5		steady

- •  H-mode facilitated by x= 0.7, x = 2, n/nG= 0.7,  DN reduction of Elms.

- • AT mode facilitated by strong shaping, close fitting wall and RWM coils.

## Slide 6

## FIRE, the Movie

**FIRE, the Movie**

- Simulation of a Standard H-mode in FIRE - TSC
- 	• CTM ≈ GLF23
- 	• m = 1 sawtooth Model - Jardin et al
- 	• other effects to be added - Jardin et al

##       How Hard should the AT be Pushed? 

**      ****How Hard should the AT be Pushed? **

**12**

## Updating FIRE AT Equilibrium Targets Based on TSC-LSC Equilibrium

**TSC-LSC equilibrium**
- Ip=4.5 MA
- Bt=6.5 T
- q(0)=3.5, qmin=2.8
- N=4.2, =4.9%, p=2.3
- li(1)=0.55, li(3)=0.42
- p(0)/p=2.45
- n(0)/n=1.4
- Stable n=
- Stable n=1,2,3 with no wall

- √V/Vo

## time,(current redistributions) 

**“****Steady-State” High- ******** Advanced Tokamak Discharge on FIRE**

- 0               1                 2                 3                4

- time,(current redistributions)

## q Profile is Steady-State During Flattop,

** ****t=10 - 41s  ~ 3.2 ********CR**

- li(3)=0.42

## Slide 12

## Neo-Classical Tearing Modes for FIRE AT Modes

- Bt=6.5 T

- Bt=7.5 T

- Bt=8.5 T

- Ro

- Ro

- Ro

- Ro+a

- Ro+a

- Ro+a

- fce=182

- fce=142

- fce=210

- fce=164

- fce=190

- fce=238

- 

- 

- 

- 

- 170 GHz

- 200 GHz

- _Target Bt=6.5-7 T for NTM control_, to utilize 170 GHz from ITER R&D
- _Must remain on LFS for resonance and use O-mode, due to high Bt_
- ECCD efficiency?? (trapping)

_**Can we rely on OKCD to suppress NTM’s far off-axis on LFS versus ECCD ?? (enhanced Ohkawa affect at plasma edge)**_

- Can we avoid NTM’s with j() and q>2.0
- or do we need to suppress them??

## J. Decker, APS 2002,MIT

**OKCD allows LFS EC deposition, with similar A/W as ECCD on HFS **

## Comments on ECCD in FIRE

- ASDEX-U shows that 3/2 island is suppressed for about 1 MW of power with IECCD/Ip = 1.6%, giving 0.013 A/W
- Ip=0.8 MA and N=2.5
- DIII-D shows that 3/2 island is suppressed for about 1.2-1.8 MW with jEC/jBS = 1.2-2.0
- Ip=1.0-1.2 MA, N=2.0-2.5
- OKCD analysis of Alcator-CMOD gives about 0.0056 A/W
- FIRE’s current requirement should be about 15 times higher than ASDEX-U (scaled by Ip and N2)
- Need about 200 kA, which would require about 35 MW?? Early detection reduces power alot according to ITER
- Do we need less current for 5/2 or 3/1, do we need to suppress them??
- Is 170 GHz really the cliff in EC technology??

- MIT, short pulse results

## FIRE EC Geometry

******pe**** > ******
**cutoff** **for 170 GHz**

**EC launcher**

******ce**** = ******

- _FIRE EC Geometry_

- Rays are bent as they  approaches pe

- Rays must be launched with toroidal directionality for CD

- n(0)=4.51020
- f pe=9√n

## Disruptions in FIRE

- Adhere to ITER disruption guidelines - any major modifications envisioned?
- quench = 0.1-0.5 ms
- dIp/dt(max) = 3 MA/ms
- Ihalo(max) = 0.25  Ip (peaking factors are to be used in Opera or VV analysis)
- Vertical disruption modeled by TSC to give dynamics and eddy currents
- dIp/dt = 3MA/ms
- Ihalo = 2 MA
- Near midplane disruption
- dIp/dt = 3 MA/ms
- Ihalo = 2 MA
- Structure model (TSC-simplified, Opera-Sandia-Ulrickson, ORNL-Nelson)

-   Are neutrally stable DN disruptions different?, less violent?,less frequent?
-   Could a fast internal coil system help ameliorate VDE disruptions?

## R&D Needed for Advanced Tokamak Burning Plasma

- •  Scaling of energy and particle confinement needed for projections of performance and ash accumulation.  Benchmark codes using systematic scans versus density, triangularity, etc.
- •  Continue RWM experiments to test theory and determine hardware requirements.  Determine feasibility of RWM coils in a burning plasma environment.
-  •  Improve understanding of off-axis LHCD and ECCD including effects of particle trapping, reverse CD lobe on edge bootstrap current and Ohkawa CD.  Develop techniques for NTM stabilization in H-Mode (10T) and AT(6.5T).
- •  Development of a self-consistent edge-plasma-divertor model for W divertor targets, and incorporation of this model into core transport model.
-  •  Determine effect of high triangularity and double null on confinement, -limits, Elms, and disruptions.

## Latest News about US Fusion Funding 

- an increase of $10,800,000 over the budget request.  The Committee is
- cautiously supportive of the Administration's proposal to re-engage in the
- International Thermonuclear Experimental Reactor (ITER) project, but is
- disappointed that the budget request provides $12,000,000 in funding for
- the U.S. ITER effort only at the expense of displacing ongoing domestic
- fusion research.  The additional $10,800,000 includes $4,000,000 for
- burning plasma experiments, including support for ITER and for the domestic
- FIRE project, $5,200,000 for fusion technology, and $1,600,000 for advanced
- design and analysis work.  If the Department intends to recommend ITER
- participation in the fiscal year 2005 budget request, the Committee expects
- the Department will so so without harm to domestic fusion research or to
- other programs in the DOE Science budget."

**Latest News about US Fusion Funding**

**House of Representatives Energy and Water SC Appropriations - July 9,03**