# Presentation: 137117

## Advanced Tokamak Regimes

**Advanced Tokamak Regimes**
** ****in the **
**Fusion Ignition Research Experiment (FIRE)**

**30th Conference on Controlled Fusion and Plasma Physics**
**St. Petersburg, Russia**
**July 10, 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**
**for the **
**  ****FIRE Collaboration**

## Topics to be Discussed

-   Vision for Magnetic Fusion Power Plant
-   Conventional Mode Operation in FIRE
-   Advanced Mode Operation in FIRE
-   O-D Systems analysis
-   1.5-D Tokamak Code Simulation
-   RWM Stabilization Concept
-  Issues Needing R&D
- Concluding Remarks

## ARIES Economic Studies have Defined Requirements

**High Power Density**
- ~ 6 MW-3
- ~10 atm

**High Power Gain**
- Q ~ 25 - 50
- nET ~ 6x1021 m-3skeV
- P/Pheat = f ≈ 90%

**Steady-State**
- ~ 90% Bootstrap

**ARIES Economic Studies have Defined Requirements**
** ****for an Attractive Fusion Power Plant**

**Plasma Exhaust**
- Pheat/Rx ~ 100MW/m
- Helium Pumping
- Tritium Retention

**Plasma Control**
- Fueling
- Current Drive
- RWM Stabilization

- Significant advances (> 10) are needed in each area.
- In addition, the plasma phenomena are non-linearly coupled.

##       Attractive Reactor Regime is a Big Step From Today  

**      ****Attractive Reactor Regime is a Big Step From Today  **

## 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
-  All metal PFCs
-  Actively cooled W divertor
-  Be tile FW, cooled between shots
-  T inventory ~ TFTR
-  LN cooled BeCu/OFHC TF
-  no neutron shield, small a
-  3,000 full pulses
-  30,000 2/3 pulses
-  X3 repetition rate since SNMS
-  Site needs comparable to previous
-      DT tokamaks.

## 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 8

## FIRE Plasma Systems are Similar to ARIES-AT

** **x = 2.0, x = 0.7
- Double null divertor
- Very low ripple 0.3%  (0.02%)

- NTM stability: LH current profile modification (’) at (5,2) @ 10T ECCD @ 180 GHz, Bo = 6.6T

- No ext plasma rotation source
- Vertical and kink passive stability: tungsten structures in blanket, feedback coils behind shield
- n=1 RWM feedback control with coils - close coupled

- 80 (90%) bootstrap current
- 30 MW LHCD and  5 MW (25 MW capable) ICRF/FW for external current drive/heating

- Tungsten divertors allow high heat flux
- Plasma edge and divertor solution: balancing of radiating mantle and radiating divertor, with Ar impurity

- n/nGreenwald ≈ 0.9,
-     H(y,2) = 1.4 (ARIES-AT)
- High field side pellet launch allows fueling to core, and P*/E= 5 (10) allows sufficiently low dilution

## 0-D Power/Particle Balance Identifies Operating Space for FIRE - AT

- Heating/CD Powers
- ICRF/FW, ≤ 30 MW
- LHCD, ≤30 MW
- Using CD efficiencies
- (FW)=0.20 A/W-m2
- (LH)=0.16 A/W-m2
- P(FW) and P(LH) determined at r/a=0 and r/a=0.75
- I(FW)=0.2 MA
- I(LH)=Ip(1-fbs)
- Scanning Bt, q95, n(0)/<n>, T(0)/<T>, n/nGr, N, fBe, fAr

- Q=5
- Constraints:
- flattop/CR determined by VV nuclear heat (4875 MW-s) or TF coil (20s at 10T, 50s at 6.5T)
- P(LH) and P(FW) ≤ max installed powers
- P(LH) + P(FW) ≤ Paux
- Q(first wall) < 1.0 MWm-2 with peaking of 2.0
- P(SOL) - Pdiv(rad) < 28 MW
- Qdiv(rad) < 8 MWm-2

**Generate large database and then screen for viable points**

## FIRE’s Q = 5 AT Operating Space

**FIRE’s Q = 5 AT Operating Space**

**Access to higher ********flat****/********j**** decreases at higher ********N****, higher B****t****, and higher Q, since ********flat**** is set by VV nuclear heating**

**Access to higher radiated power fractions in the divertor enlarges operating space significantly**

## FIRE’s AT Operating Space

- Q = 5 - 10 accessible
- N = 2.5 - 4.5 accessible
- fbs = 50 - 90+ accessible
- flat/CR = 1 - 5 accessible

- If we can access.....
- H98(y,2) = 1.2 - 2.0
- Pdiv(rad) = 0.5 - 1.0 P(SOL)
- Zeff = 1.5 - 2.3
- n/nGr = 0.6 - 1.0
- n(0)/<n> = 1.5 - 2.0

## 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 15

## 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.
- •  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.

## Concluding Remarks

- • There are a number of high leverage physics R&D items to be worked on for operation in the conventional mode and the advanced mode.   There needs to be an increased emphasis on physics R&D for aggressive advanced modes.
-  • The U.S. Administration has shown an interest in fusion and has approved joining the ITER negotiations.  Congress has also shown interest with Authorization bills that support ITER if it goes ahead, and support FIRE if ITER does not go ahead. This is consistent with the consensus in the U.S. fusion community.

**Concluding Remarks**