Plasma parameter near Ganymede

Xianzhe Jia provided his MHD simulated plasma paramters for PEP analysis.

The data file is stored in MHD_PlasmaParameters_3Rg_XianzheJia.mat file. The file is not in the pyana repository, and should be prepared separately.

File format

File is provided in the matlab format. I do not plan to convert it to any other formats (text, idl or python pickle). Use scipy.io.loadmat to load. Also, pyana.pep.mhddata provides the class PlasmaParameter 1205 as an adapter.

Detailed look into file structure

After reading the matlab formatted file, you will get a dictionary.

The dictionary has keys as:

‘X’

x coordinates. Unit of Ganymede radius, 1Rg = 2631.4 km.

‘Y’

y coordinates

‘Z’

z coordinates

‘N’

Density with the unit of /cm-3

‘Vx’

x-component of velocity with the unit of km/s

‘Vy’

y-component of velocity.

‘Vz’

z coordinates

‘Pth’

Thermal pressure with the unit of nPa.

‘T’

Temperature with the unit of eV.

All the quantities has (8000000, 1) shape. In reality, the data is organized in 3-D cartesian grid. Z is the first to rotate, Y follows and then, X. Reshape would work well. Each coordinate forms 200 data point.

Using the above information we will get the data dimension to 3-D in a straightforward way.

x = dat['X'].reshape((200, 200, 200))

The order of the argument is x, y, z. (x[:, 0, 0] == x[:, iy, iz] for arbitrary iy and iz)

The coordinate system

GPHIO system is applied. This is defined like:

x-axis

The direction of the corotation flow

y-axis

+Y points towards Jupiter

z-axis

+Z is aligned with Jupiter’s rotation axis

Implementation

The class PlasmaParameter 1205 implements the data file maneuvour.