Anomalous Dynamical Screening of Relativistic Plasma in a Magnetic Field

We study collective excitations in a relativistic collisionless plasma composed of massless fermions subject to an external magnetic field. We include dynamical electromagnetism and fluctuations of the chiral charge, while maintaining a vanishing net chiral charge. Within the framework of chiral kinetic theory, we find that the chiral anomaly gives a correction to the transverse photon self-energy and that a novel type of dynamical screening can emerge. In the strong magnetic field limit, we also show that the collective mode has a gap using the lowest Landau level approximation. We further discuss implications of the anomalous dynamical screening for neutron star phenomenology.