Interferometry observations of VHF backscatter from plasma irregularities induced by meteor in sporadic E region

With the interferometry technique implemented at the Chung-Li VHF radar, the spatial structures of the meteor-induced plasma irregularities responsible for the longpersisting (more than 4 minutes) range spread echoes are reconstructed. We found that the irregularities assemble in a clump structure centered at height 105 km with vertical extent of 3-8 km and horizontal dimension of 2-10 km. We also found that the plasma irregularities are field-aligned with appreciably narrow aspect angle. On the basis of the enormously narrow spectral width of the echoes and almost indiscernible delay between range spread echoes and meteor head echoes, we speculate that the mechanism involved in the generation of the plasma irregularities responsible for the range spread echoes is attributed to the perturbation of the intense plasma densities by the neutral turbulences excited by the large wind shear.