2-D Surface Slices

This example demonstrates add_2d_slice() — the method for rendering a 2-D surface at a fixed spherical coordinate.

Exactly one of r, t, p must be a size-1 array, pinning that coordinate. The other two axes define the surface grid. The fixed axis is inferred automatically, and the result is rendered as a quad-faced surface colored by the supplied data array.

The two most common 2-D slice orientations in solar physics are the radial shell (fixed \(r\), varying :math:` heta` and \(\phi\)) and the equatorial cut (fixed :math:` heta = pi/2`, varying \(r\) and \(\phi\)).

import numpy as np
from pyvisual import Plot3d

Radial Shell

A full spherical surface at \(r = 1\,R_\odot\) showing a synthetic low-order multipole radial field \(B_r \propto \sin(2\theta)\cos(3\phi)\). In practice this surface is produced by passing a single-index read of a PSI HDF file, but the API is identical when using NumPy arrays.

r = np.array([1.0])
t = np.linspace(0, np.pi, 100)
p = np.linspace(0, 2 * np.pi, 200)
T, P = np.meshgrid(t, p, indexing='ij')
data = np.sin(2 * T) * np.cos(3 * P)

plotter = Plot3d(off_screen=True, window_size=(500, 500))
plotter.show_axes()
plotter.add_sun()
plotter.add_2d_slice(r, t, p, data, cmap='seismic', clim=(-1, 1),
                     show_scalar_bar=False)
plotter.show()

Static Scene

Interactive Scene

Equatorial Cut

A meridional plane at \(\theta = \pi/2\) (the equatorial plane) showing the radial field \(B_r r^2\) — scaling by \(r^2\) removes the geometric falloff of a dipole and highlights the azimuthal structure at all distances from \(1\) to \(10\,R_\odot\).

t = np.array([np.pi / 2])
r = np.linspace(1, 10, 80)
p = np.linspace(0, 2 * np.pi, 200)
R, P = np.meshgrid(r, p, indexing='ij')
Br = np.cos(2 * P) / R ** 2
data = Br * R ** 2     # radially scaled flux

plotter = Plot3d(off_screen=True, window_size=(500, 500))
plotter.show_axes()
plotter.add_sun()
plotter.add_2d_slice(r, t, p, data, cmap='seismic', clim=(-1, 1),
                     show_scalar_bar=False)
plotter.show()

Static Scene

Interactive Scene