Radiation emission from plasma oscillation

It is well known that an infinite homogeneous Langmuir wave, formed by accelerating charged particles, it does not emit electromagnetic radiation because of its electrostatic nature, which is represented by the zero curl of the electric field. To realise emission, the plasma density must be tailored such that the Langmuir wave takes on a non-zero component of the curl of the electric field. The mechanisms of inverse mode conversion or travelling wave antennae leads to emission of radiation. In these mechanisms, the emphasis is on energy conversion of the Langmuir ‘wave’ to an electromagnetic wave. However, an interesting way to cause the plasma wave to emit radiation is to isolate a single ‘oscillator’ composed of a localized plasma block, i.e., a plasma dipole. An outstanding question in the realization of this idea is how to isolate the plasma oscillation from the Langmuir wave. To answer this question, we propose a novel idea of colliding detuned counter-propagating laser pulses in plasma. Simulation results show that radiation is emitted from the isolated plasma dipole