EMISSION PATTERNS OF SOLAR TYPE III RADIO BURSTS: STEREOSCOPIC OBSERVATIONS

摘要: Simultaneous observations of solar type III radio bursts obtained by the STEREO A, B, and WIND spacecraft at low frequencies from different vantage points in ecliptic plane are used to determine their directivity. The heliolongitudes sources these bursts, estimated assuming that they located on Parker spiral magnetic field lines emerging associated active regions into spherically symmetric atmosphere, estimate viewing angle, which is angle between direction source line connecting spacecraft. normalized peak intensities each R{sub j} = I{sub /{Sigma}I{sub (the subscript j corresponds WIND), defined as directivity factors determined using time profiles bursts. It shown distribution angles divides into: (1) emitting a very narrow cone centered around tangent with angular width {approx}2 Degree-Sign (2) wider widthmore » spanning {approx} - 100 {approx}100 . plots versus all three indicate emissions intense along source, steadily fall increase higher values. comparison emission patterns computed distributions ray trajectories visible range directions probably emitted fundamental mode, whereas relatively weaker wide harmonic mode.« less