Plotting

The booz_xform python module includes several routines for plotting. These functions take a Booz_xform instance as an argument. This object can be one which was used to drive the coordinate transformation. Or, this Booz_xform instance could be one in which results from an earlier transformation were loaded using the read_boozmn() function.

The plotting routine require the python matplotlib package. This package must be installed manually since it is not required for the core functionality of booz_xform and so is not installed by pip.

All plotting routines use matplotlib’s current axis. When using these routines in a script, you typically need to call plt.show() at the end to actually display the figure.

A gallery of plots that can be generated can be found in plots_demo notebook in the examples directory. The full API of the available plotting routines follow.

modeplot(b, nmodes=10, ymin=None, sqrts=False, log=True, B0=True, legend_args={'loc': 'best'}, **kwargs)

Plot the radial variation of the Fourier modes of \(|B|\) in Boozer coordinates. The plot includes only the largest few modes, based on their magnitude at the outermost surface for which data are available.

Parameters:

  • b (Booz_xform, str) – The Booz_xform instance to plot, or a filename of a boozmn_*.nc file.

  • nmodes (int) – How many modes to include

  • ymin (float) – Lower limit for the y-axis. Only used if log==True.

  • sqrts (bool) – If true, the x axis will be sqrt(toroidal flux) instead of toroidal flux.

  • log (bool) – Whether to use a logarithmic y axis.

  • B0 (bool) – Whether to include the m=n=0 mode in the figure.

  • legend_args (dict) – Any arguments to pass to plt.legend(). Useful for setting the legend font size and location.

  • kwargs – Any additional key-value pairs to pass to matplotlib’s plot command.

This function can generate figures like this:

_images/modeplot1.png _images/modeplot2.png
surfplot(b, js=0, fill=True, ntheta=50, nphi=90, ncontours=25, **kwargs)

Plot \(|B|\) on a surface vs the Boozer poloidal and toroidal angles.

Parameters:

  • b (Booz_xform, str) – The Booz_xform instance to plot, or a filename of a boozmn_*.nc file.

  • js (int) – The index among the output surfaces to plot.

  • fill (bool) – Whether the contours are filled, i.e. whether to use plt.contourf vs plt.contour.

  • ntheta (int) – Number of grid points in the poloidal angle.

  • nphi (int) – Number of grid points in the toroidal angle.

  • ncontours (int) – Number of contours to show.

  • kwargs – Any additional key-value pairs to pass to matplotlib’s contourf or contour command.

This function can generate figures like this:

_images/surfplot.png _images/surfplot2.png
symplot(b, max_m=20, max_n=20, ymin=None, sqrts=False, log=True, B0=True, helical_detail=False, legend_args={'loc': 'best'}, **kwargs)

Plot the radial variation of all the Fourier modes of \(|B|\) in Boozer coordinates. Color is used to group modes with \(m=0\) and/or \(n=0\).

Parameters:

  • b (Booz_xform, str) – The Booz_xform instance to plot, or a filename of a boozmn_*.nc file.

  • max_m (int) – Maximum poloidal mode number to include in the plot.

  • max_n (int) – Maximum toroidal mode number (divided by nfp) to include in the plot.

  • ymin (float) – Lower limit for the y-axis. Only used if log==True.

  • sqrts (bool) – If true, the x axis will be sqrt(toroidal flux) instead of toroidal flux.

  • log (bool) – Whether to use a logarithmic y axis.

  • B0 (bool) – Whether to include the m=n=0 mode in the figure.

  • helical_detail (bool) – Whether to show modes with n = nfp * m and n = -nfp * m in a separate color.

  • legend_args (dict) – Any arguments to pass to plt.legend(). Useful for setting the legend font size and location.

  • kwargs – Any additional key-value pairs to pass to matplotlib’s plot command.

This function can generate figures like this:

_images/symplot1.png _images/symplot2.png