How can plasma torches reach $28000°\text{C}$? According to this the plasma of a plasma torch can reach up to $28000$ degrees Centigrade.
How is it possible for the plasma to reach a temperature much higher than that of The Sun's surface and not completely burn and melt everything in a mile radius?
Even with the poor heat conductivity of the air this high a temperature should be more than enough to heat everything within seconds.
 A: the sun also in the corona has a temperature of 1000000 K, that is where the sun is  mostly pure plasma. and in the plasma torch it is a very small region where  you have this 28000°C, and the heat is absorbed by the nearby material to be welted.And yes it is heated in less than a second, but only at a point.
A: You are probably confusing "temperature," which is  proportional to the log(number of available energy states), with  "total energy," which depends on how many particles have a certain temperature; and then look at  how quickly they can transfer that energy to neighbors.
My "go-to" demonstration of this is to put a sheet of aluminum foil in the oven, set to maybe 240 Celsius,  and ask people to pull it out bare-handed.  It hardly even feels "warm" to the touch.  It's hot, but doesn't hold much energy.   But stick your hand into a pot full of water at, say,  65 Celsius and it'll hurt.  Cooler but lots more energy transferred into your skin.
A: If you wish to learn more, the technical concept is called “heat capacity”. If the heat capacity of something is low, then it can get very hot with relatively little energy, as is the case for your example.
