At https://www.livescience.com/space/interstellar-comet-3i-atlas-is-erupting-in-ice-volcanoes-new-images-suggest… the idea of ice volcanoes on comets is well embedded in mainstream thinking. The electric universe people disagree. Whatever is happening, the fact it occurred when the comet was at its closest approach to the Sun may suggest a connection with the solar wind – or simply solar radiation in general. All comets become active in the inner solar system – and big comets are even active in the outer solar system. This is still within the electromagnetic heart of the solar system – inside the magnetosphere that surrounds it. The link sticks strictly to a mainstream agenda but researchers have found evidence that as the comet approached the Sun a series of eruptions caused the comet to outgas more. The comet was of course also erupting water vapour consistent with the idea of an ice volcano. So, the jury is out.
The link says that scientists conclude that in spite of coming from another solar system comet 31/ATLAS has a surprising amount in common with objects in our own cosmic neighbourhood. It goes on to describe in detail what they think happens to comets as they near the Sun – and how comet 31/ATLAS conforms to the same pattern. Intriguing.