# Presentation: 064305

## Advanced Tokamak Plasmas and the Fusion Ignition Research Experiment

- Charles Kessel
- Princeton Plasma Physics Laboratory
- Spring APS, Philadelphia, 4/5/2003

## What is an Advanced Tokamak?

- The advanced tokamak plasma **simultaneously obtains**
- Stationary state
- High plasma kinetic pressure  ---->  MHD stability
- High self-driven current  ---->  Bootstrap current
- Sufficiently good particle and energy confinement  ----> Plasma transport
- Plasma edge that allows particle and power handling ---->  Boundary condition between hot core plasma and vacuum/solid walls
- The advanced tokamak is a **recognition** that the tokamak is an **integrated system** and **requires control** to succeed
- The advanced tokamak is a **tough nut to crack**

## plasma

**Transport**

**Safety factor**

**Pressure profile**

**Current profile**
**  ****(bootstrap)**

- _LHCD, FWCD, NBCD, ECCD, HHFW_

- _NBI rotation_

- _Pellet injection_

- _Plasma shaping_

- _Impurity injection_

- _RWM feedback_

- _NTM_
- _feedback_

- _Divertor_
- _pumping_

**plasma**

- _Ion/electron heating_

**Alpha heating**

*Appreciating the *_***plasma’s integrated behavior***_* is helping us *_***learn to control it***_

## Next Step Devices Must Provide the Basis for Advanced Tokamak Reactor Regime

**FIRE**

**Inductive**

**AT**

**KSTAR**

**FIRE AT is approaching the reactor AT regime**

**Present tokamak experiments are pushing the envelope**

## Local Reduction of Energy, Particle, and Momentum Transport in Plasmas

- Local Reduction of Energy, Particle, and Momentum Transport in Plasmas
- By **Manipulating**:
- Magnetic field distribution
- Momentum injection
- Electron/ion heating
- Current distribution
- Impurity injection
- D Pellet injection
- we are _**learning to control the location and width of the transport reduction**_

**thermal conductivity**

**temperatures**

**density&velocity**

**magnetic field twist**

**center**

**edge**

**ASDEX-U**

## Theory and Experiments Show That Powerful MHD Instabilities Can Be Controlled 

**HBT-EP, Columbia Univ.**

**DIII-D, General Atomics**

## Impurities Can Control Where Power from the Plasma is Deposited

- Power radiated onto high heat flux surfaces

- Power radiated more uniformly throughout vessel

## Large Plasma Self-Driven Current Fractions are Being Attained

**60-90% of the plasma current** is driven by the plasma itself, _**from its pressure gradient**_

**ASDEX-U, Germany**

**DIII-D,USA**

**Japan**

## FIRE Has Adopted the AT Features Identified by ARIES Reactor Studies 

- High toroidal field
- Double null
- Strong shaping
- Internal vertical position control coils
- Wall stabilizers for vertical and kink instabilities
- Very low toroidal field ripple
-  ICRF/FW on-axis CD

- LH off-axis CD
- NTM stabilization from LHCD, ECCD, q>2
- Tungsten divertor targets
- Feedback coil stabilization of RWMs
- Burn times exceeding current diffusion times
- Pumped divertor/pellet fueling/impurity control to optimize plasma edge

## FIRE is Aggressively Pursuing AT Control Tools

## AT Physics Control Capability on FIRE

**Strong plasma shaping and control**
**Pellet injection**
**Divertor pumping**
**Impurity injection**
**ICRF/FW (electron heating/CD) on-axis **
**ICRF ion heating on/off-axis**
**LHCD (electron heating/CD) off-axis**
**ECCD off-axis (Ohkawa current drive)**
**RWM MHD feedback control**
**t(flattop)/t(curr diff) = 1-5**
**Diagnostics**

**MHD**
**J-Profile**
**P-profile**
**Flow-profile**

## FIRE Pushes to Self-Consistently Simulate Advanced Tokamak Modes

_**0-D Systems Analysis**_**:**Determine viable operating point global parameters that satisfy constraints
_**Plasma Equilibrium and Ideal MHD Stability**_: **(JSOLVER, BALMSC, PEST2, VALEN),** Determine self-consistent stable plasma configurations to serve as targets
_**Heating/Current Drive**_: **(LSC, ACCOME, PICES, SPRUCE, CURRAY),** Determine current drive efficiencies and deposition profiles
_**Transport**_**:(GLF23 and pellet fueling models to be used in TSC)** Determine plasma density and temperature profiles consistent with heating/fueling and plasma confinement
_**Integrated Dynamic Evolution Simulations**_: **(Tokamak Simulation Code, WHIST, Baldur)**** **Demonstrate self-consistent startup/formation and control including transport, current drive, fueling and equilibrium
_**Edge/SOL/Divertor**_**:(UEDGE) **Find self-consistent solutions connecting the core plasma with the divertor

## FIRE AT Integrated Simulations Show Attractive Features

- FIRE AT **Integrated Simulations** Show Attractive Features

- Q ≈ 5

## Advanced Tokamaks --- We Want to Have It Our Way

- The **advanced tokamak** is characterized by the features we need for a **viable fusion power plant**
- Access to **this regime requires control** of the plasma and we are learning how by **penetrating** **its coupled physics**
**FIRE** is a next step burning plasma device
- Utilizing _experimental advanced tokamak_ accomplishments
- Adopting design features of _advanced tokamak reactor designs_
- Applying _integrated simulation_ tools to project the _advanced tokamak performance_
**FIRE ****can bridge the AT physics gap from present experiments to the reactor regime**_  _