nobody read this part of my post? "If all plasma blades are of the same charge they will still repel each other,"
anyhow I'm no physicist but a very high concentration of superheated plasma would act somewhat like a solid, in that coming in contact with another blade of plasma would provide resistance enough to block the attack, even apart from magnetic repulsion. The same resistance upon contact with matter would also occur, except that the plasma cut a path thru the matter quicker than any tactile feedback could possibly make you aware of resistance. The way a hot knife slides through butter with no pressure applied.
If this were not so, we would not be able to channel plasma thru metal conduits such as with the plasma propulsion engines they designed for long range space travel. Plasma does not simply phase through metal, unless hot enough to melt its way through, and likewise, high density plasma would not phase through a separate beam of high density plasma.
IE the ONLY difference is that it wont be reflecting blaster bolts
Doesn't matter if they are just the same charge the magnetic field would have to be incredibly strong.
Think about two magnets. If they are the same charge they repel correct? However think about how strong they have to be for you not to be able to force them together.
So for the lightsaber to repel another light saber it would have to have an extremely strong magnetic field to repel the other blade. So strong that you using all your force could not overcome the repulsion of it. Of course the stronger the magnetic field the farther out it goes.
So you would have light saber battles where the blades slow down as they get close to each other and never actually hit. Or the field isn't strong enough and you are able to overcome it and again the blades pass right through each other.
And if the blades are of opposite charges then they would be attracted to each other. Which would lead to some really funny lightsaber duels but again... still not a real light saber.
Trying to apply real world science to make something that came from someones imagination is not going to work. Keep in mind Lucas originally called them Laser Swords.
Oh and the Plasma would not act like a solid it would act like a gas which is what it is.