The cosmic ray flare effect

Abstract

One of the diffcoulties encountered in trying to explain the sadden increase of cosmic rays observed on the earth foliowing somae solar flares is that magnetic fields in the vicinity of the flare in the chromosphere should maintain the cosmic-ray particles in a comparatively small volume and allow them to diffuse only at a very low rate. It in thus necessary to find a mechanism by which cosmic rays can be quickly liberated and distributed through a large volume near the sun so that a maanetic path to the earth is likely. Another major problem concerns the magnetic fields that must exist at distances from the sun as great as the earth's distance in order to account for the arrival of particles in the late stages of the flare effect from a great variety of directions. The magnietic gaidance of the particles must be such as to allow them to arrive at the earth quickly in the first place, but to later give the appearance of being diffused. The first problem may be overcome by the assumption of a cooperative proangation mdechanismf cosmic rays. There is a linait on the constraining fonce that the field can exent. It is supposedmore » that when the total cosmic-ray flax exceeds a certain value the containment of ihe panticles becomes unstable and they can suddenly leak out from the front of the region in which they were continued into all or a great many directioas. The instability leads to cbuanels being established so that the cosmic rays can propagate through the fields. Such a process would not only explain how the particles get out from the strorg solar fields, but it would also explain the essential threshold nture of the flsre effect. It appears that a great many flares, if not all, produce cosmic-ray particles, but only those that produce a suficient totzi finx 10 burstt through the containing fields can show up on the earth as a sudden increase in the cosraic rate. The time and space distribution of cosmic rays reacting the eamth is discussed. (A.C.)« less