+--------------------+----------------------+-------+-----------------+
| **Princeton Plasma |                      |       |                 |
| Physics            |                      |       |                 |
| Laboratory**       |                      |       |                 |
|                    |                      |       |                 |
| **NSTX             |                      |       |                 |
| Experimental       |                      |       |                 |
| Proposal**         |                      |       |                 |
+--------------------+----------------------+-------+-----------------+
| **Title:           |                      |       |                 |
| Multi-mode beam    |                      |       |                 |
| fast ion loss      |                      |       |                 |
| power scan**       |                      |       |                 |
+--------------------+----------------------+-------+-----------------+
| **OP-XP-705**      | > **Revision:**      | >     |                 |
|                    |                      |  Effe |                 |
|                    |                      | ctive |                 |
|                    |                      | >     |                 |
|                    |                      | Date: |                 |
|                    |                      | >     |                 |
|                    |                      | > *   |                 |
|                    |                      | (Ref. |                 |
|                    |                      | >     |                 |
|                    |                      | OP-AD |                 |
|                    |                      | -97)* |                 |
|                    |                      | >     |                 |
|                    |                      | >     |                 |
|                    |                      | Expir |                 |
|                    |                      | ation |                 |
|                    |                      | >     |                 |
|                    |                      | Date: |                 |
|                    |                      | >     |                 |
|                    |                      | > *(2 |                 |
|                    |                      | >     |                 |
|                    |                      |  yrs. |                 |
|                    |                      | > u   |                 |
|                    |                      | nless |                 |
|                    |                      | >     |                 |
|                    |                      |  othe |                 |
|                    |                      | rwise |                 |
|                    |                      | > st  |                 |
|                    |                      | ipula |                 |
|                    |                      | ted)* |                 |
+--------------------+----------------------+-------+-----------------+
| **PROPOSAL         |                      |       |                 |
| APPROVALS**        |                      |       |                 |
+--------------------+----------------------+-------+-----------------+
| **Author: E. D.    |                      |       | > Date Dec. 7,  |
| Fredrickson, G     |                      |       | > 2006          |
| Fu**               |                      |       |                 |
+--------------------+----------------------+-------+-----------------+
| **ATI -- ET Group  |                      |       | > Date          |
| Leader: S A        |                      |       |                 |
| Sabbagh**          |                      |       |                 |
+--------------------+----------------------+-------+-----------------+
| **RLM - Run        |                      |       | > Date          |
| Coordinator: D     |                      |       |                 |
| Gates**            |                      |       |                 |
+--------------------+----------------------+-------+-----------------+
| **Responsible      |                      |       |                 |
| Division:          |                      |       |                 |
| Experimental       |                      |       |                 |
| Research           |                      |       |                 |
| Operations**       |                      |       |                 |
+--------------------+----------------------+-------+-----------------+
| [**Chit Review     |                      |       |                 |
| Board**            |                      |       |                 |
| (designated by Run |                      |       |                 |
| Coordin            |                      |       |                 |
| ator)]{.underline} |                      |       |                 |
+--------------------+----------------------+-------+-----------------+
| **MINOR            |                      |       |                 |
| MODIFICATIONS**    |                      |       |                 |
| (Approved by       |                      |       |                 |
| Experimental       |                      |       |                 |
| Research           |                      |       |                 |
| Operations)        |                      |       |                 |
+--------------------+----------------------+-------+-----------------+
|                    |                      |       |                 |
+--------------------+----------------------+-------+-----------------+

NSTX EXPERIMENTAL PROPOSAL

Multi-mode beam fast ion loss power scan *Assess the effects of
supra-Alfvénic fast ion driven instabilities on driven current in the
plasma core* OP-XP-705

# 1. Overview of planned experiment 

> This experiment combines ideas from three proposals. The first was a
> continuation of XP608 from the 2006 campaign to document a quiescent,
> beam heated plasma for the purpose of benchmarking the TRANSP beam and
> bootstrap current calculations (and the calculation of the beam fast
> ion profile). The second proposal was to document TAE avalanche events
> with the full range of fast MHD diagnostics, fast ion diagnostics and
> full equilibrium diagnostic set (including MSE). The third proposal
> was to explore the power (fast ion beta) dependence of TAE Avalanche
> events. It will also include a vertical NPA scan in quiescent plasmas
> and plasmas with fast ion MHD (TAE avalanches and probably fishbones).
> An attempt will also be made to do some preliminary work on HHFW
> beat-wave excitation of TAE or possibly CAE modes and HHFW
> stabilization/suppression of Angelfish in a piggy back mode.
>
> The reference shot for the second two proposals was shot 113544, or
> for a more modern shot with different beams 120124. Both were 800 kA
> shots with toroidal field current of 53 kA. However, the reference
> shot for the quiescent proposal was 121210, which also had 800 kA, but
> at a toroidal field current of 47 kA.
>
> The first part of the experiment will be to reproduce 121210, then
> increase the TF current to 53 kA, reproducing the 120124 target.
> (Actually, the current ramp rate was slightly faster in 120124, so the
> next step will be to change that, also.) If a quiescent regime can be
> found for the target shot 120124 (with source C at ≈ 60 kV), the
> density will be raised and sources B&C will be injected at 60 kV. Beam
> voltage will then be increased, and so on until the highest power
> quiescent condition is found. The best result for a quiescent plasma
> will then be documented with a vertical NPA scan, and a scan in time
> of source A turn-on to get the q-profile evolution. This may also be
> an opportunity for some correlation-reflectometry work, and if there
> have been promising results from HHFW-beatwave excitation experiments,
> they could be tried in this quiescent plasma with reflectometry
>
> Following the documentation, source voltage will be increased and/or
> density lowered until TAE bursts reappear. The best example of TAE
> avalanches were seen in shot 113544. This shot used both source A and
> B at 65 kV. It would be better if the avalanches could be generated
> with sources B and C, reserving source A at 90 kV for the MSE
> diagnostic. Shot 113546 had reasonable TAE avalanches, but they were
> accompanied by n=1 fishbones.
>
> The experiment cannot be done as piggy-back. Multiple shots at the
> right condition needed for NPA scan. Shots must be in L-mode, with
> central density ≈ 3.5 x 10^13^/cm^3^ to optimize reflectometer data.
> Depending on number of reflectometer channels, might need small
> density scan, maybe 10-20% variation.
>
> TRANSP bootstrap and beam driven current models have not been
> benchmarked at low aspect ratio. Interpretation of measured current
> profile evolution obviously requires an accurate model for these
> currents.
>
> A clean benchmarking requires an MHD quiescent discharge. This would
> be a high density, low beam voltage discharge. Source A would need to
> be stepped through to measure q-profile evolution (Source A would be
> at 90 kV, and would excite broad spectrum of \*AE modes which might
> redistribute the fast ions).
>
> HHFW beat-wave excitation of TAE will be attempted in piggy-back mode
> during this XP. Details will be worked out with RF group prior to
> executing XP, but overall strategy would be to notch neutral beams,
> whence the \*AE activity should decay on ms timescales, and pulse the
> HHFW with half of the sources shifted in frequency by ≈ 50 kHz to 100
> kHz. (The ability to sweep frequency in time would be very helpful.)
> n=3 rotation braking might be desirable to aid in matching TAE
> frequency, avoiding theoretical issues relating to sheared rotation.

# 2. Theoretical/ empirical justification

> Fast-ion redistribution or losses due to fast ion modes in ITER or
> other fusion reactors is expected to be through multi-mode transport,
> *e.g*., Alfvén avalanches. NSTX is well situated to the study of
> Alfvén avalanches. Avalanches have been observed \[Fredrickson, NF
> 06\], but in plasmas prior to routine availability of MSE. To simulate
> the effect of avalanches on fast ion confinement, we need to measure
> the amplitude (and confirm the radial eigenmode structure) of each
> mode involved in the avalanche. We need the q-profile and other
> equilibrium data for NOVA calculations of mode structure. The upgraded
> NPA and sFLIP may also help confirm the details of the predicted
> affect on fast ion transport.

# 3. Experimental run plan

> [Part A (first run day):]{.underline}
>
> Goal is to reproduce quiescent target plasma similar to 121210, then
> extend quiescent regime to parameters similar to those for shot 120124
> (higher field, fast current ramp). Plasmas will be in L-mode for this
> initial experiment; a future XP might extend this work to H-mode
> regime.
>
> **A1** Reproduce quiescent plasma as in 121210, with source C at ≈ 60
> kV 1
>
> **A2** Increase toroidal field to ≈ 53 kA, change current waveform
> (shot 120124) 1
>
> **A2.1** If not quiescent, increase density to lower beam beta 2
>
> **A3** Add source A during ramp-up (100 to 160ms), after 320 ms.
>
> **A4** Add source B at ≈ 60 kV, 1
>
> **A4.1** If not quiescent, increase density to lower beam beta 2
>
> **A4.2** If quiescent increase source B or C voltage in 5 kV steps
> until TAE appear 4
>
> **A5** Document highest power quiescent plasma -- step source A at 90
> kV
>
> Back in time from 0.32s to 0.24s in 0.2 s intervals to document q
> profile evolution,
>
> Then extend earlier pulse forward to 180ms, to 200ms. 6-8
>
> Vertical NPA scan 6-8
>
> [Part B (second run day):]{.underline}
>
> Goal is to increase fast ion beta in steps until first TAE appear,
> then continue until TAE avalanches start. First, density will be
> decreased, if necessary, to optimize reflectometer coverage. Then beam
> voltage will be increased in 5 kV steps. Best examples of TAE
> avalanches occurred in shots with sources A&B at 65 kV. We'll try that
> with B&C at 65 kV
>
> **B1** Start with best quiescent case from Part A, lower n~e~(0) ≈
> 3.5x10^13^/cm^3^ 3
>
> **B1.1** Document TAE, if they show up at lower density 4
>
> **B2** Increase beam voltage in 5 kV increments until TAE avalanches.
> 4
>
> **B3** Document q evolution during avalanches (NPA scan?) 5
>
> Evaluate data acquired to this point, return to conditions where
> documentation is uncertain. Verify that good reflectometer and MSE
> data was acquired.
>
> Repeat, as much as possible, at higher field (5.5 kG)
>
> [HHFW Beatwave TAE excitation]{.underline}
>
> It would be desirable to attempt HHFW beatwave TAE excitation during
> this experiment to provide a direct measurement of the TAE damping
> rate. At some later point in the discharge, around 350 ms, the beams
> will be notched off for about 100 ms and HHFW will be pulsed on. If
> this is considered to be useful, the notch will also be put during the
> TAE avalanches. Planning for this piggy-back operation will depend
> very much on whether we can get some run time before the experiment,
> the sweep rate possible for the beat frequency, and the difficulty in
> analysis of the data.

# 4. Required machine, NBI, RF, CHI and diagnostic capabilities

Describe any prerequisite conditions, development, XPs or XMPs needed.\
Attach completed Physics Operations Request and Diagnostic Checklist

> Part A could be done with the three reflectometer channels available
> (planned) in the second week. Some small Argon puffing might also be
> done to boost the soft x-ray signal level.
>
> For Part B, more than the standard three reflectometer channels would
> be desirable, i.e., during or after the fifth week.
>
> MSE is a must.
>
> n = 3 braking capability is strongly desired.
>
> HHFW with the capability for beat wave launching is strongly desired.
>
> Capability for vertical scan of NPA is highly desired. Alternatively,
> radial scan might be done.

# 5. Planned analysis

What analysis of the data will be required: EFIT, TRANSP, etc.

> Benchmarking TRANSP beam, bootstrap and fast ion deposition
> calculations will require extensive TRANSP analysis/simulations.
>
> Study of TAE onset, TAE avalanche threshold will require extensive
> NOVA-k and M3D-K simulations.

# 6. Planned publication of results

What will be the final disposition of the results; where will results be
published and when?

> There should be one paper on TRANSP benchmarking (Fredrickson?).
>
> There should be at least one paper on TAE avalanches (Fu?,
> Gorelenkov?)

PHYSICS OPERATIONS REQUEST

Multi-mode beam fast ion loss power scan OP-XP-705

Machine conditions (specify ranges as appropriate)

> I~TF~ (kA): **34-52** Flattop start/stop (s): **0.0/1.0**

I~P~ (MA): **0.800** Flattop start/stop (s): **0.2/0.9**

Configuration: **120124/121210**

> Outer gap (m): **\_\_\_\_\_**, Inner gap (m): **\_\_\_\_\_**
>
> Elongation κ: **\_\_\_\_\_**, Triangularity δ: **\_\_\_\_\_**
>
> Z position (m): **0.00**
>
> Gas Species: **He**, Injector: **Midplane / Inner wall / Lower Dome**
>
> NBI - Species: **D**, Sources: **A/B/C**, Voltage (kV): **90/60/60**,
> Duration (s): **0.90**

ICRF -- Power (MW): **≈ 2MW**, Phasing: **Beatwave**, Duration (s):
**0.2s**

CHI: **On / Off**

*Either:* List previous shot numbers for setup: **120124/121210**

*Or:* Sketch the desired time profiles, including inner and outer gaps,
κ, δ, heating, fuelling, etc. as appropriate. Accurately label the
sketch with times and values.

DIAGNOSTIC CHECKLIST

Multi-mode beam fast ion loss power scan OP-XP-705

+----------------------+----+-----+-----------------------------------+
| #### Diagnostic      | #  | ##  | #### Instructions                 |
|                      | ## | ##  |                                   |
|                      | #  | Des |                                   |
|                      | Ne | ire |                                   |
|                      | ed |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Bolometer --       |    |     |                                   |
| > tangential array   |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Bolometer array -  |    |     |                                   |
| > divertor           |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > CHERS              | >  |     |                                   |
|                      |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Divertor fast      |    |     |                                   |
| > camera             |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Dust detector      |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > EBW radiometers    |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Edge deposition    |    |     |                                   |
| > monitor            |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Edge pressure      |    |     |                                   |
| > gauges             |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Edge rotation      |    |     |                                   |
| > spectroscopy       |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Fast lost ion      |    | >  |                                   |
| > probes - IFLIP     |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Fast lost ion      | >  |     |                                   |
| > probes - SFLIP     |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Filtered 1D        |    |     |                                   |
| > cameras            |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Filterscopes       |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > FIReTIP            | >  |     |                                   |
|                      |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Gas puff imaging   |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Infrared cameras   |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Interferometer - 1 |    |     |                                   |
| > mm                 |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Langmuir probe     |    |     |                                   |
| > array              |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Magnetics -        | >  |     |                                   |
| > Diamagnetism       |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Magnetics - Flux   | >  |     |                                   |
| > loops              |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Magnetics - Locked | >  |     |                                   |
| > modes              |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Magnetics - Pickup | >  |     |                                   |
| > coils              |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Magnetics -        | >  |     |                                   |
| > Rogowski coils     |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Magnetics - RWM    |    |     |                                   |
| > sensors            |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Mirnov coils --    | >  |     |                                   |
| > high frequency     |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Mirnov coils --    | >  |     |                                   |
| > poloidal array     |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Mirnov coils --    | >  |     |                                   |
| > toroidal array     |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > MSE                | >  |     |                                   |
|                      |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Neutral particle   | >  |     |                                   |
| > analyzer           |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Neutron            | >  |     |                                   |
| > measurements       |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Plasma TV          | >  |     |                                   |
|                      |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Reciprocating      |    |     |                                   |
| > probe              |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Reflectometer --   | >  |     |                                   |
| > core               |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Reflectometer -    |    |     |                                   |
| > SOL                |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > RF antenna camera  |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > RF antenna probe   |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > SPRED              |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Thomson scattering | >  |     |                                   |
|                      |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Ultrasoft X-ray    | >  |     |                                   |
| > arrays             |   |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Visible            |    |     |                                   |
| > bremsstrahlung     |    |     |                                   |
| > det.               |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > Visible            |    |     |                                   |
| > spectrometers      |    |     |                                   |
| > (VIPS)             |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > X-ray crystal      |    |     |                                   |
| > spectrometer - H   |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > X-ray crystal      |    |     |                                   |
| > spectrometer - V   |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > X-ray PIXCS (GEM)  |    |     |                                   |
| > camera             |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > X-ray pinhole      |    |     |                                   |
| > camera             |    |     |                                   |
+----------------------+----+-----+-----------------------------------+
| > X-ray TG           |    |     |                                   |
| > spectrometer       |    |     |                                   |
+----------------------+----+-----+-----------------------------------+