| During a substorm on 27 January 2004, energetic particle injections associated with ULF
waves have been detected when Cluster fleet was traveling inbound in the Southern Hemisphere.
Substorm-injected energetic particles are strong and clearly modulated by these ULF waves. The ULF
waves with the period of 1 min are probably the third harmonic mode. The periodic pitch angle dispersion
signatures at 5.2–6.9 keV energy channel were detected by Cluster satellite. These thermal plasma have
high coherence with the electric field of the third harmonic poloidal mode and satisfy the drift-bounce
resonant condition of N = 2. In addition, ion outflows from the Earth’s ionosphere (tens to hundreds of eV)
are also observed to be modulated by these ULF waves. To the best of our knowledge, this is the first report
to show that ULF waves can simultaneously interact with both substorm-injected “hot” particles from the
magnetotail and cold outflow ions from the Earth’s ionosphere. |