Talk:Electromagnetic electron wave

phase velocity

 * the wave speed is the speed of light in vacuum. As the density increases, the phase velocity increases and the group velocity decreases

Does this article seriously say that the phase velocity increases from c?

TomViza 18:02, 4 June 2006 (UTC)


 * Yes. --Art Carlson 21:22, 6 June 2006 (UTC)

Thanks for that. Anyone care to explain/correct? TomViza 23:26, 27 June 2006 (UTC)


 * Where's the problem? It's only the phase velocity that is superluminal. Signals and energy travel at the group velocity, which is less than c, so there is no problem with special relativity. If you watch waves at the beach, pick out the biggest wave and follow it. It will eventually dwindle into a normal wave or get lost completely. At the same time, some normal-sized wave behind it will grow and become the biggest wave. That is, the individual crests and troughs travel faster than the body of the disturbance. In the same way, if you bang a plasma, an electromagnetic electron wave will start to propagate. This disturbance as a whole will spread out with a speed less than c, but the individual wiggles within the disturbance will be moving faster than c.--Art Carlson 07:48, 28 June 2006 (UTC)

unexplained notation
What is ωc and ωp??? Please declare and explain those before usage! Geek1337 (talk) 20:42, 19 June 2012 (UTC)
 * Fixed (albeit minimally). Art Carlson (talk) 13:05, 21 June 2012 (UTC)