Figure 1.
The two-panel schematic shows spherical geometries in a three-dimensional coordinate system with x-axis, y-axis, and z-axis. Panel A illustrates a sphere with radius R p r t and a point identified by spherical coordinates r, theta, and phi. Angular directions theta and phi are marked, and labelled vectors b, h, e, and j are shown within the sphere. Dashed circular paths indicate coordinate surfaces and reference planes. Panel B shows concentric spherical structures with an inner radius labelled R p r t and an outer radius labelled R i n s. Both panels depict geometric relationships and spatial coordinates within spherical domains.Spherical particle and the directions of the fields. (a) Particle, (b) Particle/insulation-system