Hello Dotini: The idea of me explaining this seems ludicrous to me, but here goes. My ideas on this come from reading Wal. If i screw this up please, someone, correct me.
The solar system has a positive [the sun] and negative [heliopause]. As a comet moves away from the sun it slowly becomes negatively charged. As it reaches aphelion [greatest distance from the sun] it is moving very slowly. It has been decelerating the entire outward trip. The longer this comet lingers, the more negative it becomes. After aphelion, the comet starts to accelerate towards the sun. Slowly at first. During this slow acceleration the comet is still balancing it's charge with the negative environment. I assume that at some point on the inward leg the comet would actually be balanced with the electrical environment.
Now it gets interesting. Now the comet starts to really accelerate. The now negatively charged comet enters the more positive area closer to the sun. As the differential between the negative comet and positive sun increases the comet becomes an EU laboratory. It forms a plasma sheath. When the process gets strong enough the surface of the comet starts to be electrically eroded in a process similar to electric discharge machining [EDM]. If the current becomes strong enough the comet can explode or effect the sun. I believe comet fragments were responsible for the Chicago fire, Tunguska, and the New Madrid earthquake.
Comet Elenin seems to be at the high end of long period comets. Wiki says 200 years to a few million years for long period comets. If the 3 million estimate for Elenin is correct things could be interesting. On the other hand, comets that were supposed to be spectacular were dudes. But those predictions were made in an electrically neutral world.
The link below is the good stuff. After You look at the article, i suggest the archive. It's wonderful!
http://www.holoscience.com/news.php?article=hcabb8zjmichael