Ohh, and I think I forgot to mention on my other two posts about the "source" of said discharges.

Simply put, it all traces back to, of all things, the sun.

Bear with me.

http://www.wikipedia.com/wiki/Birkeland_current
http://www.wikipedia.com/wiki/Geomagnetic_storm
http://www.wikipedia.com/wiki/Solar Flare
http://www.wikipedia.com/wiki/Coronal_mass_ejection

Long story short. Birkeland was a hella genius, and figured out where the auroras basically come from. IE, Birkeland currents coming directly from the sun in all its majesty. These currents are generally aligned to the poles (hence the more technical term field-aligned currents). We see polar auroral glow on other planets/moons in the solar system including the poles of: Saturn, Jupiter, Earth, IO, Enceladus. We also see a double-eyed vortex on both poles of Venus, exactly where we'd expect to see Birkeland currents tagging in. Uranus also displays "bright clouds" or "bright spots" around its polar regions.

Okay, that's part one. Part two is the other powerful ejections from the sun. Solar Flares, Coronal Mass Ejections and Geomagnetic Storms. These are all electromagnetic ejection of charged particles. They're often (but not always) filamented along solar distances [via magnetic self-constriction]. At some point they may intersect a planet. Tghe planet's magnetosphere deflects some of the charged particles, but some it captures. Rather obviously, this add charge to the magnetosphere, a portion of which gets transmitted down through the layers of the atmosphere to charge the layers nearer the surface. Eventually this charge build-up get too strong and causes dielectric breakdown. Okay, kiddies, what's the layman's term for dielectric breakdown in the atmosphere? Lightning! That's right!

And what happens to a planet (like mars) or other solar body (like asteroids, comets, moons) that has little to no magnetosphere and little to no atmosphere? Well, what happens when you bombard an insulating surface with high energy particles and/or free electrons?

http://205.243.100.155/frames/lichtenbergs.html

That's right, a good portion of them will get absorbed by the insulating surface and "charge" it, until it reaches a a charge that exceeds the dielectric strength of the insulating surface. What happens then? We get a process of dielectric breakdown in a catastrophic discharge. We get electron cascade and we get a massive arc of electricity at the surface (in the lab this is done with a conductor to try to channel the discharge). Not only that, but we get an actual physical change of the structure of the insulator as the electrons cascade, and we actually get a Lichtenberg figure carved into the insulator (internally and/or on the surface). This is suspiciously similar to what happens to golf courses during a lightning strike.

Hmm... Interesting no?

So, long story short, the story is complete from sun to flare and/or birkeland current to charging the surface (especially on unprotected planets like Mars), to dielectric breakdown, to lightning and scarring.

Of course, lightning may not be the only factor in the equation. Interestingly, one theory that I'm still on the fence about regards megalightning. And one theory goes that a potential impactor, like a meteorite may actually cross/puncture/breach several levels of electrical gradient in the atmosphere, while at the same time ionizing the atmosphere in a sheath around itself due to impact velocity. The difference in the electrical twist becomes that since the impactor has punctured several gradients with an ionized trail (and plasma are generally electrically conductive), it MIGHT be possible that electric charges in the different layers / shells of the planet could use the ion trail much like a conductive electrical circuit, and dump a massive quantity of "stored" electricity from said shells into the circuit, with Mars as the "ground" for the circuit and the impactor as well, basically an imperfection in the line. And if enough current gets dumped down the line, the impactor could effectively act like a blown circuit and literally blow up or blow out due to the huge electrical stresses. Meanwhile the whole system still has velocity and mass, so it's streaking toward "ground" and further ionizing the pathway. Well, if it's broken up and there's still electricity being dumped down the circuit perhaps this IS how we get both an electrical feature and a feature consistent with an impactor and a plasma. As I said, I'm not entirely sold on the idea, but it is intriguing and not TOO far off from BOTH current theories. An interesting example might be the Tunguska Event. early last century (around 1900-1908-ish, I forget exactly when). But basically, there was a meteor-like impact, but it was extremely anomalous, since NO CRATER was ever found. At dead center were trees still standing but stripped of bark, outside of dead center trees were flattened outward in a giant circle. All sorts of other interesting and anomalous things happened too. But one thing that was definitely found was scattered hematite spherules. So, whatever it was most likely rained them or created them on the ground. Electrical arcs are known to produce them in the lab. And there was no impact crater. So the question of what happened at Tunguska has been largely unsolved ever since. The punctured electrically charged layers with a conductive ion trail seems like a fairly plausible explanation, ending with circuit fault and subsequent break up of the impactor. But the electron cascade having already been started by the interceding conductive ion trail continued as any breakdown would. And Tunguska event chronicles seem to support that hypothesis as well. Pretty much everyone noted repeated "cannon blast" type sounds continuing for a while. This could relatively easily be explained by successive return strokes of electrical discharge punctuated by dart leaders just like you get an a lightning discharge And these are generally very fast strokes, so it probably would sound like world war 3 starting if it continued for any significant length of time.

To some degree the models do overlap and could actually work in unison, which is probably why someone suggested that particular version of events. Andit would still preserve the impactor-as-initiator, but once the impactor breaks up due to massive electrical stress put on it by the circuit, it would be much easier for the electrical concretion effect to take over once the pieces are small enough. Interesting, I'll have to give that one more thought. Though I think the case for "Spiders" as lichtenbergs stands pretty well on its own as a lightning/dielectric breakdown discharge phenomenon independent of impact. All that lightenbergs need is an insulator sufficiently charged, a dielectric breakdown and an electron cascade within the insulator / charged medium. So, that could be accomplished simply by cosmic ray bombardment from the sun, especially considering spiders are preferentially banded around the south pole, and the south pole is aligned toward the sun at perihelion, getting much more bombardment than the north pole does in alignment at aphelion. I think that pretty squarely takes care of the preferentiality of the south pole for spiders formation. Though honestly, I wouldn't be surprised if a few "spider" formations show up in the north here and there, but in smaller quantities/concentrations than the south pole.

Okay, that ended up being longer than intended. So, I guess I'll stop there. Hopefully you see/understand the model in more detail now? (Electricity also, in my opinion, solves the channels-over-hills or channels "over" other channels issues more effectively than fluid dynamics, since we know that fluids generally don't flow up-hill, preferring to puddle or flow around-hill; electricity only cares about charge and surface/air conductivity and will flow over whatever features it likes with all but impunity as the arc wanders. And when water or fluids hit another channel they don't punch through the other wall and keep going, they use the pre-existing channels and generally flow downhill via the path of least resistance; electrical arcs aren't so picky and may also form secondary channels at or near right angles).

End.