首页|Quantifying errors in 3D CME parameters derived from synthetic data using white-light reconstruction techniques

Quantifying errors in 3D CME parameters derived from synthetic data using white-light reconstruction techniques

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Current efforts in space weather forecasting of CMEs have been focused on predicting their arrival time and magnetic structure. To make these predictions, methods have been developed to derive the true CME speed, size, position, and mass, among others. Difficulties in determining the input parameters for CME forecasting models arise from the lack of direct measurements of the coronal magnetic fields and uncertainties in estimating the CME 3D geometric and kinematic parameters after eruption. White-light coronagraph images are usually employed by a variety of CME reconstruction techniques that assume more or less complex geometries. This is the first study from our International Space Science Institute (ISSI) team "Understanding Our Capabilities in Observing and Modeling Coronal Mass Ejections", in which we explore how subjectivity affects the 3D CME parameters that are obtained from the Graduated Cylindrical Shell (GCS) reconstruction technique, which is widely used in CME research. To be able to quantify such uncertainties, the "true" values that are being fitted should be known, which are impossible to derive from observational data. We have designed two different synthetic scenarios where the "true" geometric parameters are known in order to quantify such uncertainties for the first time. We explore this by using two sets of synthetic data: 1) Using the ray-tracing option from the GCS model software itself, and 2) Using 3D magnetohydro-dynamic (MHD) simulation data from the Magnetohydrodynamic Algorithm outside a Sphere code. Our experiment includes different viewing configurations using single and multiple viewpoints. CME reconstructions using a single viewpoint had the largest errors and error ranges overall for both synthetic GCS and simulated MHD white-light data. As the number of viewpoints increased from one to two, the errors decreased by approximately 4° in latitude, 22° in longitude, 14° in tilt, and 10° in half-angle. Our results quantitatively show the critical need for at least two viewpoints to be able to reduce the uncertainty in deriving CME parameters. We did not find a significant decrease in errors when going from two to three viewpoints for our specific hypothetical three spacecraft scenario using synthetic GCS white-light data. As we expected, considering all configurations and numbers of viewpoints, the mean absolute errors in the measured CME parameters are generally significantly higher in the case of the simulated MHD white-light data compared to those from the synthetic white-light images generated by the GCS model. We found the following CME parameter error bars as a starting point for quantifying the minimum error in CME parameters from white-light reconstructions: ∆θ (latitude)=6°_(-3°)~(+2°), ∆ø (longitude)=11°_(-6°)~(+18°), ∆γ (tilt)=25°_(-7°)~(+8°), ∆α(half-angIe)=10°_(-6°)~(+12°), ∆h (height)=0.6_(-0.4)~(+1.2)R_⊙, and ∆κ (ratio)=0.l_(-0.02)~(+0.03).

Coronal mass ejectionsSolar coronaRemote-sensing observations

Christine Verbeke、M. Leila Mays、Christina Kay、Pete Riley、Erika Palmerio、Mateja Dumbovic、Marilena Mierla、Camilla Scolini、Manuela Temmer、Evangelos Paouris、Laura A. Balmaceda、Hebe Cremades、Juergen Hinterreiter

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Solar-Terrestrial Centre of Excellence-SIDC, Royal Observatory of Belgium, 1180 Brussels, Belgium||Centre for mathematical Plasma Astrophysics (CmPA), KU Leuven, 3001 Leuven, Belgium

Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA

Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA||Department of Physics, The Catholic University of America, Washington, DC 20064, USA

Predictive Science Inc., San Diego, CA 92121, USA

Hvar Observatory, Faculty of Geodesy, University of Zagreb, HR-10000 Zagreb, Croatia

Solar-Terrestrial Centre of Excellence-SIDC, Royal Observatory of Belgium, 1180 Brussels, Belgium||Institute of Geodynamics of the Romanian Academy, 020032 Bucharest-37, Romania

Space Science Center, University of New Hampshire, Durham, NH 03824, USA||CPAESS, University Corporation for Atmospheric Research, Boulder, CO 80301, USA

Institute of Physics, University of Graz, 8010 Graz, Austria

George Mason University, Fairfax, VA 22030, USA||Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723, USA

Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771, USA||George Mason University, Fairfax, VA 22030, USA

Grupo de Estudios en Heliofisica de Mendoza, CONICET, Universidad de Mendoza, 5500 Mendoza, Argentina

Space Research Institute, Austrian Academy of Sciences, 8042 Graz, Austria||Institute of Physics, University of Graz, 8010 Graz, Austria

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2023

Advances in space research: The official journal of the Committee on Space Research
  • 56