The cone of acceptance and magnetic rigidity cutoff of galactic cosmic ray particles for different models of the International Geomagnetic Reference Field from 1965-2015 in the Deblin airport, Poland

Abstract

We present the results of computations of the trajectories (the asymptotic latitude and asymptotic longitude) and the magnetic cutoff rigidity of galactic cosmic ray (GCR) particles for the airport Deblin, Poland (geographical latitude 51°33′32′′ N, geographical longitude 21°50′53′′ E) based on the numerical integration of equations of motion of charged particles of cosmic rays in the Earth’s magnetic field. The set of allowed trajectories at a given site on the surface of the Earth is called the asymptotic cone of acceptance The initial distance from the center of the Earth was taken to be 20 km above the Earth’s surface. At about this altitude, most cosmic rays undergo nuclear collisions. Calculations were made for different of models of the International Geomagnetic Reference Field (IGRF) from 1965–2015. The IGRF is an internationally agreed and widely used mathematical model of the Earth’s magnetic field of internal origin. Each constituent model of the IGRF is a set of spherical harmonics of degree n and order m, representing a solution to Laplace’s equation for the magnetic potential arising from sources inside the Earth at a given epoch. In all asymptotic direction calculations, we used sixth-degree expansion of geomagnetic field model. Schmidt normalized spherical harmonic coefficients were taken for the epochs from 1965 to 2015. Knowledge of asymptotic directions and the magnetic rigidity cutoff is important from the point of view of study different classes of cosmic rays variations intensity and anisotropy.