# Plasma parameter calculator

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### Contents:

- Overview
- Inputs
- Outputs
- Bugs/Caveats
- History
- Other MPE/ISSI PlugIns

### Overview

This PlugIn calculates various plasma parameters such as :
- 0) magnetic pressure (Pb = B^2/mu0)
- 1) perpendicular plasma pressure (Pp = nkT_perp)
- 2) full pressure (Pf = 2nkT_perp + nkT_par)
- 3) total pressure (P = Pb + Pp)
- 4) plasma beta (Pp/Pb)
- 5) temperature anisotropy (Tpar/Tperp - 1)
- 6) pressure ratio alfa = nt(Tpar-Tperp)/B^2/mu0
- 7) entropy = Pf/n^5/3 (n=density) - 8) sound speed, cs = 989 sqrt(P/n) [km/s
- 9) plasma frequency fpe = 8968 sqrt(n),
- 10) ion inertial length (l = 227/n)
- 11) ion gyro radius (r = 1300*[sqrt(T_perp)] / B)
- 12) Alfven speed Va = B/sqrt(mu rho)

### Input data

All inputs are optional and the number of output parameters depend on the given inputs. The inputs are automatically joined to the timetags of the input vector from the plasma temperature (alternatively density, velocity or B-field).

For compatibility with both Cluster and THEMIS data sets, the temperatures can be supplied either as a tensor (typically THEMIS) or as a parallel and a perpendicular temperature. In the former case, insert the temperature tensor in slot 3, and leave input slot 4 empty.

### Outputs

The outputs are written to the worklist. Output depends on inputs given. See above for a complete list of output paramaters.

### Outputs

20 Nov, 2008 - updated this help text. 02 Feb, 2008 - all input optional, output as function of inputs. 31 Jan, 2008 - accept temperature tensor in units of eV (i.e., Themis). 27 Jun, 2006 - added sound speed + plasma frequency
07 Oct, 2004 - revised version

### Bugs/Caveats

Note that some of the calculations are estimations, proxies.
Calculations for Mach number and Alfven speeds are not double checked. Use with care.

### Other MPE/ISSI PlugIns

- Generic residue analysis of conservation laws
- Vector calculator/ Curlometer
- DeHoffmann-Teller analysis
- Solar wind utility. Calculates IMF clock angle, energy input, dynamic pressure etc.
- EDI filter utility
- Separate plasma velocity into paralell and perpendicular components
- Plasma calculator. Calculates plasma beta, magnetic pressure, resistivity inertial lengths etc.
- Modify, mask and manipulate components of a vector
- Construct a matrix time series from scalar time series

SEH, SEHDATE, 2006