one cool thing about radiation is that it isn't traditionally visible to humans. you can sort of see the heat wave refraction on really active sources. were this person to begin using this power it would be at least noticeable at the point of generation if not totally encompassing the person's body with those refractions.

It is also worth commenting that such control could modify the at least two fundamental interactions. being an amateur nuclear physicist, hazarding a guess at what would happen to the environment around the user instead of the user/target themselves i think would be more appropriate.

Hm that's actually interesting, so let me just make sure I fully understand what you're saying , so technically the radiation itself isn't visible so therefore wouldn't truly have any affect on his appearance per say (especially not the green glow the media portrays) but rather invisible, with the only real indication being the environment around him such as the air. Aldo I remember reading that when certain radioactive particles are underwater they cause a blue glow, but it that actually accurate.

I believe what you are referring to is known as Cherenkov Radiation. very neat effect, but I don't believe we've observed it happening in air. another neat thing, we have developed cloud chambers which allow us to visualize ionizing radiation. as far as visual representations in media this might be the most "accurate" or plausible

bowl0stu‭ Hm alright that's pretty useful, it may admittedly mean I'll have to reconsider how he looks when his powers are active if the most realistic and plausible indication is the air getting wavy and possible to damage to various parts of the environment, still I think I can find ways to make it work. Anything else I should probably take into consideration

different types of radiation affect materials differently. that sounds mundane and obvious, but we didn't have the scientific understanding of it for decades. It might be worth considering the half-life of atoms as well. the stronger a source, the quicker it decays and that isn't limited by radiation type so, theoretically, blasting a thing with X number of radiations produces X number of decay rates.

unless you intend to get really deep in the weeds with hard science explanations, have your character be cautious of expenditure and "charge levels". the rest can be flavorful descriptions

bowl0stu‭ Hm ok so if I'm understanding you correctly (chances are I'm not but still) if he uses too little too much radiation it could potentially make his attacks less effective or last for less time right, that could be interesting