Question

Difference between bremsstrahlung and inverse bremsstrahlung

Answer 1

Hello. I've read some article that the inverse bremsstrahlung is the process that a free electron absorbs a photon while it collides with an ion, so it is 3-body process. But I don't know how it is physically explanined. Why the electron that is in collision with the ion can absorb the photon? And I would like to know the relationship between the laser energy and the plasma electron density. I've also read the following relations. 1. If plasma angular frequency wp < laser angular frequency w : the plasma is transparent for the laser. 2. If wp = w : the plasma becomes a perfect mirror. 3. If wp > w : the plasma becomes a good laser absorber. I can understand the 1st case as it is easily proved in a undergraduate level plasma physics course. 2nd case...is what I may accept.. But 3rd case...how can it is physically explained? Thanks for reading this and I look forward to get any response.