The original interpretation of the electrostatic noise observed during the AMPTE solar wind lithium releases is complemented to clarify the nature of the intervening instabilities, the role of the particle populations on wave excitation, and the generation of the higher-frequency (a few kilohertz) noise. The results suggest that the lower frequencies are created by an electron beam instability providing growth within a broad range of wave vector directions, whereas a negative-energy, slow proton beam mode might contribute to the existence of the higher noise frequencies.