SH33B-2467
Deriving Kinematic Properties of Non-Radial, Asymmetric and Deflecting CMEs: Methods and Implications
Wednesday, 16 December 2015
Poster Hall (Moscone South)
Barbara J Thompson1, Paulett Creyke Liewer2, M. Leila Mays3, Ian G Richardson4, RyunYoung Kwon5, Leon Ofman3, Pertti A Makela3, Jack Ireland6, Phillip Hess5 and Zachary Waldron7, (1)NASA Goddard Space Flight Center, Greenbelt, MD, United States, (2)Jet Propulsion Laboratory, Pasadena, CA, United States, (3)Catholic University of America, Washington, DC, United States, (4)University of Maryland College Park, CRESST and Department of Astronomy, College Park, MD, United States, (5)George Mason University Fairfax, Fairfax, VA, United States, (6)ADNET Systems Inc. Greenbelt, Greenbelt, MD, United States, (7)american university, washington, United States
Abstract:
An improved understanding of the kinematic properties of CMEs and CME-associated phenomena has several impacts: 1) a less ambiguous method of mapping propagating structures into their inner coronal manifestations, 2) a clearer view of the relationship between the “main” CME and CME-associated brightenings, and 3) an improved identification of the heliospheric sources of shocks, Type II bursts, and SEPs. However, there are several challenges in characterizing the kinematic properties of CMEs. Most rapidly-evolving eruptions are accompanied by changes in the surrounding corona. The larger the impact on the surrounding corona, the more difficult it is to separate the “main” CME from the CME-associated brightenings. Complicating the issue is the range of observed propagation properties: super-radial expansion, asymmetric expansion, non-radial propagation, and alterations in the direction of propagation. These properties can be a function of both the internal magnetic structure of the CME and the structure of the corona through which the CME is propagating. While the relative contribution of internal/external factors can be difficult to assess, it is of fundamental importance because it not only reveals the nature of CMEs but also CME-associated phenomena such as EUV waves, Type II radio bursts, shocks, and SEPs. Most halo CMEs are a combination of both the “main” CME and the CME-associated brightenings, but new diagnostic methods such as time convolution mapping can help separate the CME mass from the impacted corona. Additionally, while most CME-fitting methods assume symmetry about the radial direction, adaptive methods allow us to study highly asymmetric CME expansion and take into account the fundamentally different natures of the CME and the shocked/deflected corona. Several methods will be examined, and each has their respective strengths and weaknesses; for example, the difference between the direction of a highly non-radial CME and a sun-centered model’s orientation can exceed 45 degrees, which impacts our ability to correctly assess changes in propagation direction and the causes of these changes. We examine the assumptions inherent in these methods and how they may produce artifacts that can influence conclusions about CME kinematics.
