Electromagnetic Waves Generation By The Hybrid Modulational Instability

An improved model of the fundamental plasma emission of type III solar radio bursts is presented. It is shown<br>that nonlinear conversion of a traveling Langmuir pump wave into an electromagnetic wave can occur via either<br>convective or absolute hybrid modulational instabilities, resulting from the coupling of two wave triplets, with<br>the Langmuir pump wave and ion-acoustic daughter wave common to both wave triplets. The properties of<br>these four-wave hybrid modulational instabilities are studied using the observed interplanetary parameters.