Hello, im new to the these forums. I recently read the article in the Wikipedia about this force (Abraham-Lorentz) and I can't understand how it can only depent on the "jerk" (that is the acceleration's derivative). Maybe i miss something, but this seems quite impossible to me: What happens if the charge is undergoing a constant acceleratoin? In this case the "jerk" will be zero and, according to the given there formula, so will be the reaction force. But still, according to the Larmor formula, the charge will be emitting energy. So where does that emitted energy come from if there is no reaction force? This sounds like a way to construct a perpetual motion machine of the first type, doesn't it? As i inspected the given derivation of that formula, i noticed 2 problems with it: 1) it makes the arbitrary assumption that the motion is periodic and heavily relies on it. 2) at the end the derivation basically says that if the definite integrals of two periodic functions over one period are equal then the functions are one and the same, which is nonsense. So this makes the given "derivation" totally invalid. What do you people think?