This appears to be an ordinary lenticular cloud, except for that steadily glowing ring at the base. To be shaped like that, a plasma would need to be generated artificially, and, in any case, no naturally occurring plasma would remain stable for more than a few seconds. One other explanation is that the cloud is being lit from below, but there is no indication of any large lighted area under it, such as a stadium with a ring of floodlights. Lastly, it could be lit from within. If so, then what would be in it?