# Bootstrap dependence on plasma profile parameters

## Abstract

The bootstrap fraction, I{sub bs}/I{sub p}, and the shape of the bootstrap current density, J{sub bs}(r), can depend sensitively on the shape of the plasma profiles. Beginning with Hirshman`s form for the bootstrap current density, and making a large aspect ratio expansion (proceeding two orders in the square root of the inverse aspect ratio, {epsilon}), we derive an expression for the bootstrap fraction of the form I{sub bs}/I{sub p} = {epsilon}{sup {1/2}}{beta}{sub p}C{sub bs}({alpha}{sub n}, {alpha}{sub T}; {alpha}{sub J}, {Zeta}, {epsilon}) which depends explicitly on the peakedness of the density, temperature, and current. Examination of contours of constant I{sub bs}/I{sub p} in the space of {alpha}{sub n}, {alpha}{sub T} and consideration of the shape of the bootstrap current density help identify operating regimes for tokamaks which optimize bootstrap current drive.

- Authors:

- Publication Date:

- Research Org.:
- Princeton Univ., NJ (United States). Plasma Physics Lab.

- Sponsoring Org.:
- USDOE, Washington, DC (United States)

- OSTI Identifier:
- 10167485

- Report Number(s):
- PPPL-2854

ON: DE92018963

- DOE Contract Number:
- AC02-76CH03073

- Resource Type:
- Technical Report

- Resource Relation:
- Other Information: PBD: Aug 1992

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; TOKAMAK DEVICES; BOOTSTRAP CURRENT; CURRENT DENSITY; ASPECT RATIO; MAGNETIC FIELDS; 700350; PLASMA PRODUCTION, HEATING, CURRENT DRIVE, AND INTERACTIONS

### Citation Formats

```
Pomphrey, N.
```*Bootstrap dependence on plasma profile parameters*. United States: N. p., 1992.
Web. doi:10.2172/10167485.

```
Pomphrey, N.
```*Bootstrap dependence on plasma profile parameters*. United States. doi:10.2172/10167485.

```
Pomphrey, N. Sat .
"Bootstrap dependence on plasma profile parameters". United States.
doi:10.2172/10167485. https://www.osti.gov/servlets/purl/10167485.
```

```
@article{osti_10167485,
```

title = {Bootstrap dependence on plasma profile parameters},

author = {Pomphrey, N.},

abstractNote = {The bootstrap fraction, I{sub bs}/I{sub p}, and the shape of the bootstrap current density, J{sub bs}(r), can depend sensitively on the shape of the plasma profiles. Beginning with Hirshman`s form for the bootstrap current density, and making a large aspect ratio expansion (proceeding two orders in the square root of the inverse aspect ratio, {epsilon}), we derive an expression for the bootstrap fraction of the form I{sub bs}/I{sub p} = {epsilon}{sup {1/2}}{beta}{sub p}C{sub bs}({alpha}{sub n}, {alpha}{sub T}; {alpha}{sub J}, {Zeta}, {epsilon}) which depends explicitly on the peakedness of the density, temperature, and current. Examination of contours of constant I{sub bs}/I{sub p} in the space of {alpha}{sub n}, {alpha}{sub T} and consideration of the shape of the bootstrap current density help identify operating regimes for tokamaks which optimize bootstrap current drive.},

doi = {10.2172/10167485},

journal = {},

number = ,

volume = ,

place = {United States},

year = {Sat Aug 01 00:00:00 EDT 1992},

month = {Sat Aug 01 00:00:00 EDT 1992}

}