A concept to measure the inner solar system magnetic field
{"Image DocumentName": "A concept to measure the inner solar system magnetic field", "Image ImageDescription": "Zodiacal light is scattered sunlight off interplanetary dust grains. Dust grains rotate when illuminated, and become charged when exposed to UV and charged particles. A rotating charged grain will align itself with mag field. Alignment of a cloud of dust grains will produce polarized scattered light when illuminated. Using polarimetry measurements and knowledge of dust grain optical extinction coefficient, the mag field direction can be inferred. Measuring the interstellar magnetic field remotely as it traverses interplanetary space will provide significant advancement in our ability to predict the impact of space weather on Earth and at other magnetized bodies. Zodiacal light is a faint glow that appears close to the Sun in ecliptic is composed of scattered light and thermal emission from interplanetary dust grains. Composition? Silicates, olivine, peculiar shapes. Dust grains respond to directional incident light by rotating about a preferential axis determined by the size, shape and surface properties of the grain. (Abbas et al. ApJ 614, 781, 2004) \u2013 radiative torque. Dust grains are electrically charged when exposed to UV light (positive) and plasmas (negative). The residual charge on the grain depends on the surface work function of the grain, the light intensity and plasma density - reference. A rotating charged object will align itself along the magnetic field direction \u2013 two primary mechanisms, not well established which is the dominant. The alignment of a cloud of dust grains will produce polarized light \u2013 this is seen in interstellar space. In fact interstellar dust was discovered in the 1940\u2019s by analysis of contaminant polarized light in astrophysical observations \u2013 reference. Using polarimetry measurements with the knowledge of the optical extinction coefficient of the dust grains, and the number density of dust grains, the magnetic field direction can be inferred.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}