# Presentation: 009861

## Research directions for wave-particle interactions in 2007

- E D Fredrickson
*PPPL*
*WP SFG, Nov. 15, 2006*

## Waves&particles has a Joule-level milestone in FY07

- Effort will be to extend previous work to non-linear regime.
- Emphasis on complete diagnostic sets to allow full benchmarking of simulations

## Five generic fast-ion physics areas 

- Joule-milestone requires plan in December
- Need to develop plan, present at forum.
- Target is to acquire necessary data for M3D, Nova, Orbit, etc.
- Physics of possibly new or unique fast-ion instabilities
- Energetic Ion Phase-space structures
- Fast ion transport by “other” MHD
- Develop *AE quiescent NB-heated regime (ISD)
- RF stochastic thermal ion heating

## Slide 4

## Physics of possibly new or unique fast-ion instabilities

- Finish study of Alfv_x0005_én Cascades
- Show conversion to TAE?
- More extensive critical beta scaling study
- Documentation of Alfvén-acoustic mode
- Bounce-resonance fishbones
- No MSE data as yet
- Better documentation of eigenfunction, NPA/FLIP
- Candidate for Orbit calculations
- Non-linear wave coupling (f.b.-TAE-GAE-CAE)
- Better experimental data to guide theoretical progress?

## Low e Alfvén Cascades

- Present only in low /q2 plasmas.
- Explore beta scaling at different toroidal fields
- GAM/BAE convert to TAE at saturation - should be able to see this.

## Energetic Ion Phase-space structures:Non-linear saturation, interaction and evolution of *AEs

- Angelfish (GAE or CAE hole-clumps)
- RF power scan with fast scan
-  “TAE” hole-clumps
- Understand threshold for generation
- Alfvén Avalanches
- Careful documentation of amplitude
- Model phase-space-island overlap condition
- Classic fishbones (perhaps finished)
- Candidate for NPA hole-clump measurements?

## Frequency sweeping implies coherent structures: particle trapping in phase space 

*Frequency sweeping implies coherent structures: particle trapping in phase space *

- GAE/CAE fits frequency and resonance conditions at r/a=0.2/0.5, = - |k||vA| + ci

- Mirnov signal at the edge

- TRANSP distribution function andbeam ion resonances

- From Mirnov signal observations we can potentially infer (Berk, iaea'06)
-   - mode growth rate
-   - physics of wave-particle interaction
-   - fast-ion phase space diffusivity
-   - effects of additional scattering from HHFW on wave particle structures

## Explore fast-ion phase-space island overlap regime with full diagnostic coverage – including MSE

- NSTX observes that multi-mode TAE bursts induce larger fast-ion losses than single-mode bursts:

*1% neutron rate decrease:*

*5% neutron rate decrease:*

- TAE avalanches cause enhanced fast-ion losses.
- Potential to model  island overlap condition with full diagnostic set.

*Explore fast-ion phase-space island overlap regime with full diagnostic coverage – including MSE*

- E. Fredrickson, Phys. Plasmas **13**, 056109 (2006)

## Develop *AE quiescent regime (ISD)
Validate bootstrap and beam-driven current models

Fast ion transport by “other” MHD
Sawteeth
Internal kink modes
NTMs

RF stochastic thermal ion heating
Measure antenna coupling to CAE/GAE
Initial experiments to launch waves.

- Validate bootstrap and beam-driven current models
- Fast ion transport by “other” MHD
- Sawteeth
- Internal kink modes
- NTMs
- RF stochastic thermal ion heating
- Measure antenna coupling to CAE/GAE
- Initial experiments to launch waves.

## "Strawman" list of XP's

- Alfvén Cascades/TAE hole-clumps
- (800kA with He puffing)
- HHFW to suppress TAE hole-clumps
- TF scans to explore effect of beta on Cascades
- Measure conversion to TAE with reflectometer
- Bounce-resonance fishbones and Alfvén Acoustic modes
- (1 MA with He puffing)
- Document q-profile during mode activity.
- Measure eigenfunctions with sxi/reflectometer

## "Strawman" list, continued

- CAE/GAE Hole-clumps/stochastic heating study
- Explore CAE/GAE growth rate in various regimes
- Estimate maximum heating power from CAE
- Use HHFW to control frequency chirping
- Develop *AE quiescent regime
- Validation of TRANSP bootstrap and beam driven current models.