The excitation of waves at frequencies &ohgr;103 &OHgr;(H+)/ C, &OHgr; being the H+ gyrofrequency, and C the velocity of light in vacuum).

Warm ion effects on the waves are examined; when k⊥=k⊥rl(H+)>0.3, where rl(H+) is the H+ Larmor radius in a He+--H+ plasma, the excited waves are the electrostatic-ion cyclotron (EIC) waves. Because of their phase velocity Vp≫&ngr;te, these EIC waves are pure ion Bernstein (PIB) waves. The characteristics of the electron beam-excited PIB waves are compared with their counterpart, the neutralized ion Bernstein (NIB) waves, which are EIC waves excited by drifting bulk electrons. The consideration of electrostatic waves in the frequency band &OHgr;(H+)<&ohgr;<&ohgr;lh shows that the B-P waves with k⊥rl(H+)≪1 have considerably larger temporal growth rates than the EIC waves.

The interconnections between LH and B-P waves are found to be similar to those between EIC and B-P waves; B-P waves have long perpendicular wavelengths (&lgr; ⊥) while EIC and LH waves have comparatively much shorter ones. The relevance of ICRC and PIB waves to satellite observations of waves in the ELF band is discussed. The B-P waves appear to be similar to the electrostatic broadband noise emissions in the frequency range from below the ion cyclotron frequency to the lower hybrid frequency observed from various satellites in the auroral and cusp regions.