The sun routinely produces energetic electrons in its outer atmosphere that subsequently travel through interplanetary space. These electron beams generate Langmuir waves in the background plasma, producing type III radio bursts that are the brightest radio sources in the sky (Suzuki and Dulk, 1985). These solar radio bursts also provide a unique opportunity to understand particle acceleration and transport, which is important for our prediction of extreme space weather events near the Earth. However, the formation and motion of type III fine frequency structures (see Figure 1) is a puzzle, but is commonly believed to be related to plasma turbulence in the solar corona and solar wind.