The Cluster spacecraft often cross the midaltitude cleft/cusp and observe a very well defined “electron‐only cleft” region consisting of electron injections without magnetosheath ions. This region contains soft suprathermal (<500 eV) electron bursts in antifield and/or field‐aligned directions. We present an example of such observations which shows that the O+ ion outflow at midaltitudes appears just poleward of the open‐closed boundary simultaneously with electron injections and was observed in the cleft, cusp, and mantle in the form of narrow energy beam. Inside the “electron‐only” cleft the suprathermal electron bursts are strongly correlated with strong O+ and H+ ion heating and with localized extra low frequency (ELF) (1–10 Hz) magnetic field wave power with broadband spectra. Our study shows that strong ion heating was observed only in the region with electron field‐aligned anisotropy more than 2. In addition, comparison of particle data from two spacecraft, which crossed the heating region with a time difference of 4 min, shows the correlation between ion outflow fluxes and fluxes of the injected electrons. Whereas ELF electromagnetic waves are localized inside the ion heating region, ELF electrostatic waves are detected throughout the cleft/cusp/mantle regions, where strong ion heating was not observed, suggesting that electromagnetic ELF waves heat ions in the cleft region. Owing to the absence of magnetosheath ions and strong field‐aligned currents, we suppose that inside “electron‐only” cleft region the suprathermal electron bursts are most likely an energy source for the wave destabilization. We suggest that the location of the heating region and the level of the outflow ion fluxes could be related to electron injection in the cleft in such events.
