Institute of Astronomy

Deciphering the Enigma of the Cosmic Ray Anisotropy

SpeakerTalk DateTalk Series
Vanessa López-Barquero ()3 May 2023Institute of Astronomy Seminars


Over the past decade, various experiments, such as IceCube and HAWC, have observed cosmic-ray anisotropy at different angular scales in a wide energy range. However, no comprehensive or satisfactory explanation has been put forth to date. The arrival distribution of cosmic rays at Earth is the convolution of the distribution of their sources and of the effects of geometry and properties of the magnetic field through which particles propagate. It is generally believed that the anisotropy topology at the largest angular scale is adiabatically shaped by diffusion in the structured interstellar magnetic field. On the contrary, the medium-and small-scale angular structure could be an effect of nondiffusive propagation of cosmic rays in perturbed magnetic fields. A possible explanation for the observed anisotropy at the TeV energy scale may be the effect of particle propagation in the heliosphere. Charged particles that the Sun continuously emits envelop our planet and its neighbours. This creates the heliosphere, a massive bubble that surrounds the Sun and deforms the interstellar medium’s magnetic field. In this talk, we explore the possibility that the heliosphere affects the cosmic ray energy and arrival distributions.


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