Search Publications
Connecting Speeds, Directions and Arrival Times of 22 Coronal Mass Ejections from the Sun to 1 AU
Luhmann, J. G.; Möstl, C.; Farrugia, C. J. +15 more
Forecasting the in situ properties of coronal mass ejections (CMEs) from remote images is expected to strongly enhance predictions of space weather and is of general interest for studying the interaction of CMEs with planetary environments. We study the feasibility of using a single heliospheric imager (HI) instrument, imaging the solar wind densi…
Predicting the Sun's Polar Magnetic Fields with a Surface Flux Transport Model
Hathaway, David H.; Upton, Lisa
The Sun's polar magnetic fields are directly related to solar cycle variability. The strength of the polar fields at the start (minimum) of a cycle determine the subsequent amplitude of that cycle. In addition, the polar field reversals at cycle maximum alter the propagation of galactic cosmic rays throughout the heliosphere in fundamental ways. W…
Formation of a Double-decker Magnetic Flux Rope in the Sigmoidal Solar Active Region 11520
Cheng, X.; Ding, M. D.; Zhang, J. +5 more
In this paper, we address the formation of a magnetic flux rope (MFR) that erupted on 2012 July 12 and caused a strong geomagnetic storm event on July 15. Through analyzing the long-term evolution of the associated active region observed by the Atmospheric Imaging Assembly and the Helioseismic and Magnetic Imager on board the Solar Dynamics Observ…
Structures of Interplanetary Magnetic Flux Ropes and Comparison with Their Solar Sources
Qiu, Jiong; Hu, Qiang; Dasgupta, B. +2 more
Whether a magnetic flux rope is pre-existing or formed in situ in the Sun's atmosphere, there is little doubt that magnetic reconnection is essential to release the flux rope during its ejection. During this process, the question remains: how does magnetic reconnection change the flux-rope structure? In this work, we continue with the original stu…
New Insights into the Physical Nature of Coronal Mass Ejections and Associated Shock Waves within the Framework of the Three-dimensional Structure
Zhang, Jie; Kwon, Ryun-Young; Olmedo, Oscar
We present new insights into the physical nature of coronal mass ejections (CMEs) and associated shock waves within the framework of the three-dimensional (3D) structure. We have developed a compound model in order to determine the 3D structure of multiple fronts composing a CME, using data sets taken from STEREO, SDO, and SOHO. We applied the met…
The Solar Energetic Particle Event on 2013 April 11: An Investigation of its Solar Origin and Longitudinal Spread
Lario, D.; Zhang, J.; Kwon, R. -Y. +4 more
We investigate the solar phenomena associated with the origin of the solar energetic particle (SEP) event observed on 2013 April 11 by a number of spacecraft distributed in the inner heliosphere over a broad range of heliolongitudes. We use extreme ultraviolet (EUV) and white-light coronagraph observations from the Solar Dynamics Observatory (SDO)…
Deciphering Solar Magnetic Activity. I. On the Relationship between the Sunspot Cycle and the Evolution of Small Magnetic Features
Cirtain, Jonathan W.; Wang, Xin; McIntosh, Scott W. +9 more
Sunspots are a canonical marker of the Sun's internal magnetic field which flips polarity every ~22 yr. The principal variation of sunspots, an ~11 yr variation, modulates the amount of the magnetic field that pierces the solar surface and drives significant variations in our star's radiative, particulate, and eruptive output over that period. Thi…
Asymmetry in the CME-CME Interaction Process for the Events from 2011 February 14-15
Temmer, M.; Veronig, A. M.; Vršnak, B. +1 more
We present a detailed study of the interaction process of two coronal mass ejections (CMEs) successively launched on 2011 February 14 (CME1) and 2011 February 15 (CME2). Reconstructing the three-dimensional shape and evolution of the flux ropes, we verify that the two CMEs interact. The frontal structure of both CMEs, measured along different posi…
Tracking the Evolution of a Coherent Magnetic Flux Rope Continuously from the Inner to the Outer Corona
Cheng, X.; Ding, M. D.; Zhang, J. +6 more
The magnetic flux rope (MFR) is believed to be the underlying magnetic structure of coronal mass ejections (CMEs). However, it remains unclear how an MFR evolves into and forms the multi-component structure of a CME. In this paper, we perform a comprehensive study of an extreme-ultraviolet (EUV) MFR eruption on 2013 May 22 by tracking its morpholo…
Observational Characteristics of Coronal Mass Ejections without Low-coronal Signatures
Berghmans, D.; Seaton, D. B.; D'Huys, E. +1 more
Solar eruptions are usually associated with a variety of phenomena occurring in the low corona before, during, and after the onset of eruption. Though easily visible in coronagraph observations, so-called stealth coronal mass ejections (CMEs) do not obviously exhibit any of these low-coronal signatures. The presence or absence of distinct low-coro…