Preface

Abstract

G P ZankEditor, Proceedings of the 18th Annual International Astrophysics Conference,Center for Space Plasma and Aeronomic Research (CSPAR) and Department of SpacePhysics, University of Alabama in Huntsville, Huntsville AL 35805, USAE-mail: garyp.zank@gmail.comThe 18th Annual International Astrophysics Conference was held at the Sheraton Pasadena, Pasadena, California, USA from February 18 to February 22, 2019. The theme of the meeting was "The Physics of Energetic Particles: Universal Processes from the Solar Corona to the Very Local Interstellar Medium and the Physics they Enable.” Energetic particles are ubiquitous throughout the solar wind, being integral to the solar corona, accelerated by interplanetary shock waves, present in the quiet solar wind, possibly accelerated by magnetic flux ropes or magnetic islands in the vicinity of the heliospheric current sheet, at planetary bow shocks, present in the distant heliosphere and the heliospheric termination shock, in the inner heliosheath, and now observed by Voyager 1 in the very local interstellar medium. Although numerous mechanisms have been identified that accelerate particles, no consensus exists as to which is primary, and indeed several acceleration processes can operate simultaneously in close proximity. The acceleration of particles to high energies represents a fundamental dissipative process for the plasma and can therefore modify the underlying plasma physical processes in important ways. The meeting explored observations, theories, and looked forward to anticipated new missions that will shine a light on this theme, the Parker Solar Probe and IMAP. The 18th AIAC explored these topics via a combination of invited 25 minute talks and a few 40 minute plenary talks.The 18th AIAC also celebrated Prof. J.R. (Randy) Jokipii’s 80th birthday. Randy has been a centralfigure in the physics of energetic particles and transport, including particle acceleration, particularly at shock waves, and the modulation of cosmic rays in the heliosphere. His seminal early paper, “Cosmicray propagation. I. Charged particles in a random magnetic field” defined the field for decades after its publication in 1966. This meeting was an opportunity to celebrate Randy’s accomplishments with some selected plenary presentations.Finally, there are several people to thank for their kindness and considerable help with the 18th AIAC. Adele Corona suffered a horrific car accident on the second day of the meeting. She has thankfully largely recovered. However, we are profoundly grateful to Prof.’s Dave McComas and Nathan Schwadron for selflessly stepping forward to taking over the running and management of the meeting after Adele was rushed to hospital. Their kindness and organizational skills ensured that the meeting continued with virtually no interruption. I should like to thank them both and of course Adele Corona for another outstanding meeting, and her help in providing the logistical support for this volume of papers.