Multipoint observations of chorus and plasmaspheric hiss waves

Plasmaspheric hiss is a wideband, incoherent, whistler-mode plasma wave that is found predominantly in inner magnetospheric high-density plasma regions such as the plasmasphere or plasmaspheric drainage plume. The origin of plasmaspheric hiss has been a topic of intense study and some controversy ever since its discovery in the late 1960’s. A recent set of modeling studies has shown that a different plasma wave, namely whistler-mode chorus, could be responsible for creating plasmaspheric hiss by propagating from its source region in the equatorial plasmatrough, and into the plasmasphere. Early coordinated observations made simultaneously on multiple THEMIS probes have shown excellent consistency between models and data, but later results concerning the nature of chorus waves and its relation to pulsating aurora, the discovery of low-frequency hiss, and coincident observations between high L-shell chorus and hiss have shown that there are facets of the chorus-hiss connection that are still a puzzle. In this talk, we briefly review the chorus-hiss connection mechanism and focus on recent results and open questions.