HR: 09:00h
AN: U11A-02 INVITED     [Abstracts]
TI: Space Weather From Explosive Events at the Sun
AU: * Mason, G M
EM: glenn.mason@umail.umd.edu
AF: Dept Physics and IPST, University of Maryland, College Park, MD 20742 United States
AB: Space Weather is a broad new field of research that seeks to understand short-term disturbances in the Earth-Sun system that can directly affect life and society. The importance of Space Weather has grown in direct proportion to our society's increasing use of advanced technological systems that can be affected by transient conditions in the Earth-Sun system. Communications systems, satellite and Space Station operations, astronauts, and airline passengers have all been impacted by Space Weather events. Although Space Weather events have many causes, the most extreme are associated with explosions in the solar corona. The explosions occur when large magnetic loop structures become unstable and release much of their energy in a matter of minutes. This unleashes a sequence of events, including rapid heating of the Earth's atmosphere from UV radiation and filling the inner solar system with high energy ionizing radiation. Finally, if the explosion occurs close to the middle of the solar disc, a shock wave from the explosion will impact and energize the Earth's magnetosphere one or two days later. Understanding these events involves solving a large group of scientific questions, such as why the magnetic loops go unstable; how they lose their energy; how the shock is formed and how it interacts with material along its path to energize ions to a significant fraction of the speed of light. The reaction of the Earth's magnetosphere and radiation belts to the impact of such a shock, and the eventual effects on the Earth's atmosphere are further broad areas of inquiry that seek to understand the final stages of the event. Over half of the SH sessions at this AGU meeting deal with aspects of such problems, and a new NASA program (Living With a Star) is dedicated to understanding this system with an eventual goal that will enable U.S. forecasting. A broad new set of observations along with extensive development of theories and numerical models will be needed to achieve this goal. This tutorial will introduce the topic, focusing on scientific investigations involving the shocks and high speed ions (Solar Energetic Particles) associated with these events. The generation of high speed ions, like many aspects of Space Weather, is of broad interest since it occurs at many sites through the solar system and universe.
DE: 7513 Coronal mass ejections
DE: 7519 Flares
DE: 7807 Charged particle motion and acceleration
DE: 7851 Shock waves
DE: 2118 Energetic particles, solar
SC: Union [U]
MN: 2004 AGU Fall Meeting