Figure 1. Two minutes of data from a nightside auroral pass on January 24, 1997. From top to bottom, the panels show the electron energy spectrogram (all pitch angles), the ion pitch angle spectrogram for 3–25000 eV from an electrostatic analyzer, the H⁺ energy spectrogram, the He⁺ energy spectrogram, the O⁺ energy spectrogram, energy flux (excluding the plasma sheet population) for the three major ion species, number flux (excluding the plasma sheet population) for the three major ion species, and the ELF electric field spectrogram with a line denoting the local proton gyrofrequency. Plasma sheet ions were excluded by setting the upper energy limit of the integrations to the energy above 100 eV with the lowest energy flux. A BBELF ion conic is seen at 12:45:30–12:45:50, and an EMIC ion conic is seen at 12:46:10–12:46:30 (these intervals are indicated with vertical dashed lines).