I can say that lightsabers supposedly do utilize intense heat; the reason they don't burn everyone within their proximity is because of the built-in force containment field. Another thing to keep in mind is that manufactored plasma tends to be much hotter than its naturally occuring counterpart. On the sun's surface, things can get to be about 1-3 million degrees farenheit, which is extremely high. But compared to the capabilities of even today's technology, isotopes can be heated to temperatures as hot as 150-250 million degrees farenheit. Or more. As you can see, those figures are vastly different, and I daresay the technology in Star Wars is easily capable of crafting a potentially hotter plasma, though any number higher than that is mere speculation. Logical assumption, but still speculation. When it comes to the melting point of secondary adamantium, I think it's safe to assume that the temperature extremes required to put it in a liquid state exceed 1,000,000 degrees. I say this because primary adamantium has withstood nuclear explosions, which are known to reach 150 million degrees. Though not as durable, secondary adamantium must not be that far behind, relatively speaking. Though that much is at least debatable. But now we have a better idea of what the heat may or may not be like within the blade of a lightsaber. When it comes to Thor's hammer or Hulk's fists, I could actually work out how much kinetic force is behind their blows--at least, at minimum. If I did that, we could have a figure for what the force "must not fall below", so to speak. But a note: if you're reading a comic at all, prepare yourself emotionally and psychologically for some intense physics rap3.