The Faraday Effect Tracker of Coronal and Heliospheric Structures (FETCH) instrument

There continue to be open questions regarding the solar wind and coronal mass ejections (CMEs). For example: how do magnetic fields within CMEs corotating/stream interaction regions (CIRs/SIRs) evolve in inner heliosphere? What is radially distributed profile of shock-driving CMEs? internal structure that cause storms? It clear these involve configurations transient interplanetary plasma structures, for which we have limited knowledge. In order better understand origin field variability steady-state structures events, it necessary probe Earth-directed structures/disturbances. This goal Multiview Observatory Solar Terrestrial Science (MOST) mission ( Gopalswamy et al., 2022 ). MOST answer aforementioned questions, propose instrument concept Faraday Effect Tracker Coronal Heliospheric (FETCH), a simultaneous quad-line-of-sight polarization radio remote-sensing instrument. With FETCH, spacecraft beams passing through Sun–Earth line offer possibility obtaining information conditions via analysis propagation effects such as rotation wave dispersion, provide total electron content (TEC). FETCH instrument, one ten instruments proposed hosted on mission. The will an unprecedented opportunity achieve NASA’s heliophysics science “explore characterize physical processes space environment from Sun”