
'source level' reactions and reactivity addition
Just to add a little physics here...
The problem I see with eddy currents 'kick starting' a reaction in the white dwarf is that the sudden addition of reactivity [i.e. the gravitational compression] is *ALSO* likely to cause an uncontrolled reaction and *EXPLOSION* rather than a 'kick start' of the star.
Here's why:
Fusion and fission share a few similar *kinds* of parameters, reactivity being one of them. In the case of fusion, a major part of the reactivity consists of heat and density. The fusion reaction in a star is stable because the expansion force from the fusion reaction is balanced by gravity. Too much of one, the star goes 'boom', or collapses onto itself and goes out.
I would expect that because one fusion leads to another, you'd have a lifecycle time, delaying effects, and 'reactivity' (related to the effective neutron multiplication factor for fission; for fusion, it would be related to the ability of the energy from one fusion reaction to trigger others). When you have a sudden increase in reactivity, it's likely in a fusion reaction (as it is in a fission reaction) that you get a sudden 'jump' in the reaction rate that's somewhat proportional to the reactivity addition rate (this would be due to various factors that would be common in the reactivity equations of both fusion and fission). When the power levels of a nuclear reactor are unstable [a lot of chaotic activity, like a shut down fission reactor or a 'brown dwarf' star] then sudden spikes in the reaction rate might trigger an unknowable "super power level surge", high enough to explode instead of 'just starting up'. Or not.
The SL-1 incident (see https://en.wikipedia.org/wiki/SL-1 ) was a case where a shut down fission reactor went 'prompt critical' due to sudden reactivity addition, and experienced a 'prompt jump' in power levels (followed by 'prompt criticality' where power multiplied in microseconds instead of 100's of milliseconds) from a shut down condition to a 'thousands times maximum' power level (20GW according to the article, in a 3MW reactor) in a few milliseconds, burned nearly ALL of the nuclear fuel in that time period, and caused a 'water hammer' when all of the cooling water covering the core suddenly flashed to steam and pushed the remaining water up like a big piston, faster than you can blink, forcing the reactor vessel and attached components to jump 9 feet into the air, etc. etc. very very bad contamination, core meltdown, dead people, yotta yotta. Yuck. Photo of what was left of the the melted/sploded core on the web page.
Assuming that sudden dwarf star restarts might act *like* *that*, because of the addition of reactivity by tidal forces and other 'black hole' things, if it's too quick, dwarf star go *BOOM*. My opinion.