(a) One-minute averages of the 300–800 keV electron intensities as measured in the eight sectors of E6 on board Helios-1. The four electron events have been identified with the numbers ﹩\#1﹩ to ﹩\#﹩ 4. (b) 45 s measurements of the solar wind speed as measured by the plasma experiment E1 on board Helios-1. (c) One-minute averages of the magnetic field magnitude as measured by the flux gate magnetometer E3 on board Helios-1. (d) Elevation angle and (e) azimuthal angle of the magnetic field in the Spacecraft Solar Ecliptic (SSE) coordinate system. (f) First-order (A₁/A₀) anisotropy along the magnetic field direction. (g) Second-order (A₂/A₀) anisotropy.