Plasma Filter is Free
Plasma is available for free. After downloading the installation file, the filter may be installed using Adobe Extension Manager CS6 (right-click the Plasma_Noise_v100.zxp file for a context menu). The filter runs on 8- and 16-bit RGB or grayscale images or layers. See the documentation and several examples for more information.
Plasma may also be installed via the Adobe Exchange CS6 panel right inside Adobe Photoshop CS6 for Windows. If you do not already have Adobe Exchange installed, you can download Adobe's extension for free at this link.
After installing the extension, the Adobe Exchange panel is accessible through the Window → Extensions → Adobe Exchange sub-menu option. You may search for “Plasma” if it is not visible. After restarting Photoshop, you can access the filter through the Filter → Render sub-menu.
While the filter is distributed for free through Adobe Exchange, the code, executable, and accompanying files are still copyrighted (at least currently).
Unless otherwise stated, all content and images are copyright © 2013 Peter Ronhovde
Images of the Sun are from NASA archives.