Evolution of Global‐Scale Coronal Magnetic Field due to Magnetic Reconnection: The Formation of the Observed Blob Motion in the Coronal Streamer Belt

Abstract

Recent SOHO/LASCO/EIT observations showed that the global corona at the minimum phase of cycle 22 is an organized, simple, and persistent dipolar configuration streamer belt (Michels). But the low-lying, closed-loop, multipolar magnetic structure of the inner corona at low- to mid-latitudes revealed in EIT and LASCO images is not static. It stretches continuously outward, feeding plasma into higher coronal structures and eventually into the solar wind, including plasma blobs (Sheeley et al.; Wang et al.). To understand the physics of this slow dynamic evolution process, we use a two-dimensional, planar, resistive MHD model and observed pre-event characteristics for the model input to simulate the formation and propagation of these observed plasma blobs. It seems that reconnection processes among the low-lying multipolar coronal loops and their overlying streamers cause the slow time evolution. The motion of plasma blobs frequently observed by LASCO C2/C3 is indeed reproduced by this model through reconnection in the multipolar loops. Results presented in this paper are the global field evolution, mass, momentum, and energy transport from the inner corona to the outer corona and up into the streamer belt region where slow solar wind forms. We conclude that these plasma blobs may be the origin of the lumps in the solar wind observed in interplanetary space.