The Production of Antiprotons in the Interstellar Gas by Propagating Cosmic Rays

Abstract

The available measurements on the cosmic ray $\bar p/p$-ratio show an excess of antiprotons above predictions derived in the framework of the standard picture of cosmic ray origin and propagation. We have present a detailed discussion of the equilibrium antiprotonproton ratio predictions calculated in the Standard Leaky Box Model and in the diffusive reacceleration model, where cosmic ray particles are reaccelerated due to gyroresonant interaction with hydromegnetic waves. It could be shown that the calculated $\bar p/p$ ratio is enhanced in the diffusive reacceleration model compared to that derived from the Leaky Box Model, but it remains difficult to bring it into agreement with the data.