Plasma Physics Seminar ( Phys 769)

Yakov Dimant, Boston University Evolution of meteor plasma trails: electric fields and diffusion A meteoroid penetrating the Earth's atmosphere leaves behind a trail of dense plasma in the E-region ionosphere, a region where electrons are strongly magnetized while ions are demagnetized due to their frequent collisions with neutrals. While radar measurements of meteor trail evolution have been collected and used to infer meteor and atmospheric properties since the 1950s, no accurate quantitative model of trail fields and diffusion exists. We have developed analytical theory and simulations of trail plasma physics which applies to the majority of small meteors. This study provides quantitative knowledge of the spatial distribution and dynamics of the plasma density and electric field. Structure of plasma density is important for specular radar echoes. The ambipolar electric field can drive plasma instabilities resulting in non-specular radar echoes.