# magnetics¶

Contacts: Nikolas Logan, Stefano Munaretto

## Short Description¶

Visualization and mode analysis for 3D magnetics, 3D coils and bdot sensors

## Long Description¶

This module can be used to fit toroidal and poloidal basis functions. The fits use an least-squares SVD solution, allowing a condition number threshold to limit mode inclusion sensitivities. The design matrix of this fit can use basis functions that take into account the finite toroidal and poloidal extent of the magnetic sensors or fit center points (as is standard practice for prescribing 3D coil currents). Basis functions can also include a temporal element omega*t, where omega can be prescribed or taken from an existing fit (i.e. a coil array rotation).

Raw data can be windowed, de-trended, and band-pass filtered. Noise is removed using a conditioning of the channel-by-time data matrix, which removes the incoherent (noise) component of the signal.

The module includes a number of visualizations helpful for describing and understanding the diagnostic set. It also includes a number of 1D and 2D visualizations of the data and modal fits..

The module can also be used to produce spectrograms and perform FFT of bdot signals.

## Typical workflows¶

The 3D magneitcs part of this module is used to:

Fetch raw magnetics and diagnostic data in human readable groupings (i.e. arrays)

Prepare raw data by removing drifts, smoothing, isolating frequencies of interest, compensating vacuum pickup, etc.

Fit 3D magnetics and/or coil currents to modal basis functions

Plot the sensor geometries, raw and prepared signals, and fits

The spectrogram part of this module is used to:

Fetch raw magnetics info and data for only 2 selected sensors

Compute FFT

Plot the spectrogram

Plot FFT details for a given time interval

Plot relative phases for the complete array

## Supported devices¶

DIII-D (3D)

NSTX/NSTX-U (spectrogram)

## Relevant publications¶

E.J. Strait, J.D. King, J.M. Hanson, and N.C. Logan, Review of Scientific Instruments 87, 11D423 (2016).

J.D. King, E.J. Strait, R.L. Boivin, D. Taussig, M.G. Watkins, J.M. Hanson, N.C. Logan, C. Paz-Soldan, D.C. Pace, D. Shiraki, M.J. Lanctot, R.J. La Haye, L.L. Lao, D.J. Battaglia, A.C. Sontag, S.R. Haskey, J.G. Bak, R.J. La Haye, L.L. Lao, D.J. Battaglia, A.C. Sontag, S.R. Haskey, and J.G. Bak, Review of Scientific Instruments 85, 83503 (2014).

E.J. Strait, Review of Scientific Instruments 77, 23502 (2006).

## Contributors¶

List of contributors sorted by number of lines authored:

```
2863 Stefano Munaretto
2213 Nikolas Logan
512 Oak Nelson
245 Fusion Bot
236 Clayton Myers
35 Orso Meneghini
2 Sterling Smith
2 David Eldon
```

## Submodules¶

None

## Users¶

List of usernames sorted by number of module imports: **munarettos**, **nlogan**, **mortonl**, **herfindalj**, **logannc**, **nelsonand**, **willensdorferm**, **myersc**, **bergmannm**, **churchillr**, **clementm**, **eidietis**, **gagek**, **houshman**, **huqiming**, **kyungjin**, **laggnerf**, **lyonsbc**, **pandyam**, **weisbergd**, **boyermd**, **degrandchampg**, **jianx**, **jorge**, **jriqueze**, **knolkerm**, **krietedm**, **lizeyu**, **lvovskiya**, **meneghini**, **snyder**, **tomas**, **wangy**, **xingz**