No, a charged particle does not always generate electromagnetic radiation when it moves uniformly. In order for a charged particle to emit electromagnetic radiation, its motion must involve acceleration or deceleration. Uniform motion, where the particle moves at a constant velocity in a straight line, does not produce radiation.
This behavior is governed by Maxwell's equations, which describe the fundamental laws of electromagnetism. According to these equations, an accelerated charged particle emits electromagnetic radiation. The radiation is a result of the changing electric and magnetic fields associated with the acceleration.
When a charged particle moves uniformly in a straight line, it does not undergo acceleration. As a result, there is no change in the electric and magnetic fields surrounding the particle, and no radiation is emitted.
However, if the charged particle accelerates or decelerates, its motion causes changes in the electric and magnetic fields, leading to the emission of electromagnetic radiation. The emitted radiation carries away energy from the particle's motion.
It's important to note that even in the absence of radiation, a moving charged particle still generates an electric and magnetic field, as described by the laws of electrostatics and magnetostatics. These fields exist irrespective of the presence or absence of radiation. However, the emission of electromagnetic radiation specifically requires acceleration or deceleration of the charged particle.