# MHD Modeling of Conductors at Ultra-High Current Density

## Abstract

In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator we have revisited a problem first described in detail by Heinz Knoepfel. MITLs of previous pulsed power accelerators have been in the 1-Tesla regime. Z's disc transmission line (downstream of the current addition) is in a 100-1200 Tesla regime, so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using the MHD code MACH2 we have been investigating conductor hydrodynamics, characterizing the joule heating, magnetic field diffusion, and material deformation, pressure, and velocity over a range of current densities, current rise-times, and conductor materials. Three purposes of this work are ( 1) to quantify power flow losses owing to ultra-high magnetic fields, (2) to model the response of VISAR diagnostic samples in various configurations on Z, and (3) to incorporate the most appropriate equation of state and conductivity models into our MHD computations. Certain features are strongly dependent on the details of the conductivity model. Comparison with measurements on Z will be discussed.

- Authors:

- Publication Date:

- Research Org.:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

- Sponsoring Org.:
- USDOE Office of Defense Programs (DP) (US)

- OSTI Identifier:
- 8997

- Report Number(s):
- SAND99-0480C

TRN: US0102015

- DOE Contract Number:
- AC04-94AL85000

- Resource Type:
- Conference

- Resource Relation:
- Conference: 12th IEEE International Pulsed Power Conference (PPC), Monterey, CA (US), 06/27/1999--06/30/1999; Other Information: PBD: 30 Jun 1999

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 43 PARTICLE ACCELERATORS; ACCELERATORS; CURRENT DENSITY; HYDRODYNAMICS; JOULE HEATING; CONDUCTOR DEVICES; DESIGN; M CODES; MAGNETOHYDRODYNAMICS; EQUATIONS OF STATE

### Citation Formats

```
Asay, J R, Desjarlais, M P, Douglas, M R, Frese, M H, Hall, C A, Morse, R L, Reisman, D, Rosenthal, S E, Spielman, R B, and Stygar, W A.
```*MHD Modeling of Conductors at Ultra-High Current Density*. United States: N. p., 1999.
Web.

```
Asay, J R, Desjarlais, M P, Douglas, M R, Frese, M H, Hall, C A, Morse, R L, Reisman, D, Rosenthal, S E, Spielman, R B, & Stygar, W A.
```*MHD Modeling of Conductors at Ultra-High Current Density*. United States.

```
Asay, J R, Desjarlais, M P, Douglas, M R, Frese, M H, Hall, C A, Morse, R L, Reisman, D, Rosenthal, S E, Spielman, R B, and Stygar, W A. Wed .
"MHD Modeling of Conductors at Ultra-High Current Density". United States. https://www.osti.gov/servlets/purl/8997.
```

```
@article{osti_8997,
```

title = {MHD Modeling of Conductors at Ultra-High Current Density},

author = {Asay, J R and Desjarlais, M P and Douglas, M R and Frese, M H and Hall, C A and Morse, R L and Reisman, D and Rosenthal, S E and Spielman, R B and Stygar, W A},

abstractNote = {In conjunction with ongoing high-current experiments on Sandia National Laboratories' Z accelerator we have revisited a problem first described in detail by Heinz Knoepfel. MITLs of previous pulsed power accelerators have been in the 1-Tesla regime. Z's disc transmission line (downstream of the current addition) is in a 100-1200 Tesla regime, so its conductors cannot be modeled simply as static infinite conductivity boundaries. Using the MHD code MACH2 we have been investigating conductor hydrodynamics, characterizing the joule heating, magnetic field diffusion, and material deformation, pressure, and velocity over a range of current densities, current rise-times, and conductor materials. Three purposes of this work are ( 1) to quantify power flow losses owing to ultra-high magnetic fields, (2) to model the response of VISAR diagnostic samples in various configurations on Z, and (3) to incorporate the most appropriate equation of state and conductivity models into our MHD computations. Certain features are strongly dependent on the details of the conductivity model. Comparison with measurements on Z will be discussed.},

doi = {},

url = {https://www.osti.gov/biblio/8997},
journal = {},

number = ,

volume = ,

place = {United States},

year = {1999},

month = {6}

}