Instantaneous rest-frame no Lorentz force

[johne1618]

Is it valid to analyse the equation of motion of an electron in its instantaneous rest-frame in which it feels a force from the electric field only with no magnetic Lorentz force component?

 

[vin300]

In its rest frame, the electron feels a force from both the electric and magnetic fields of the laboratory frame. The transformation is:
E'_parallel= E_parallel
E'_perp. =γ(E_perp. + vxB/c)

 

[Meir Achuz]

Vin300 is right if you want to know the rest frame force in terms of E and B in a different frame. In its res frame, an electron feels only the Lorentz force of the E field in that frame, with no magnetic component.