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Title: Predicting the Magnetic Field of Earth-impacting CMEs

Abstract

Predicting the impact of coronal mass ejections (CMEs) and the southward component of their magnetic field is one of the key goals of space weather forecasting. We present a new model, the ForeCAT In situ Data Observer (FIDO), for predicting the in situ magnetic field of CMEs. We first simulate a CME using ForeCAT, a model for CME deflection and rotation resulting from the background solar magnetic forces. Using the CME position and orientation from ForeCAT, we then determine the passage of the CME over a simulated spacecraft. We model the CME’s magnetic field using a force-free flux rope and we determine the in situ magnetic profile at the synthetic spacecraft. We show that FIDO can reproduce the general behavior of four observed CMEs. FIDO results are very sensitive to the CME’s position and orientation, and we show that the uncertainty in a CME’s position and orientation from coronagraph images corresponds to a wide range of in situ magnitudes and even polarities. This small range of positions and orientations also includes CMEs that entirely miss the satellite. We show that two derived parameters (the normalized angular distance between the CME nose and satellite position and the angular difference between themore » CME tilt and the position angle of the satellite with respect to the CME nose) can be used to reliably determine whether an impact or miss occurs. We find that the same criteria separate the impacts and misses for cases representing all four observed CMEs.« less

Authors:
;  [1];  [2];  [3]
  1. Solar Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  2. University of Colorado/Cooperative Institute for Research in Environmental Sciences and National Oceanic and Atmospheric Administration/Space Weather Prediction Center, Boulder, CO 80505 (United States)
  3. Astronomy Department, Boston University, Boston, MA 02215 (United States)
Publication Date:
OSTI Identifier:
22663860
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 835; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; FORECASTING; IMAGES; MAGNETIC FIELDS; MASS; ROTATION; SATELLITES; SIMULATION; SOLAR CORONA; SPACE; SPACE VEHICLES; SUN

Citation Formats

Kay, C., Gopalswamy, N., Reinard, A., and Opher, M., E-mail: christina.d.kay@nasa.gov. Predicting the Magnetic Field of Earth-impacting CMEs. United States: N. p., 2017. Web. doi:10.3847/1538-4357/835/2/117.
Kay, C., Gopalswamy, N., Reinard, A., & Opher, M., E-mail: christina.d.kay@nasa.gov. Predicting the Magnetic Field of Earth-impacting CMEs. United States. doi:10.3847/1538-4357/835/2/117.
Kay, C., Gopalswamy, N., Reinard, A., and Opher, M., E-mail: christina.d.kay@nasa.gov. Wed . "Predicting the Magnetic Field of Earth-impacting CMEs". United States. doi:10.3847/1538-4357/835/2/117.
@article{osti_22663860,
title = {Predicting the Magnetic Field of Earth-impacting CMEs},
author = {Kay, C. and Gopalswamy, N. and Reinard, A. and Opher, M., E-mail: christina.d.kay@nasa.gov},
abstractNote = {Predicting the impact of coronal mass ejections (CMEs) and the southward component of their magnetic field is one of the key goals of space weather forecasting. We present a new model, the ForeCAT In situ Data Observer (FIDO), for predicting the in situ magnetic field of CMEs. We first simulate a CME using ForeCAT, a model for CME deflection and rotation resulting from the background solar magnetic forces. Using the CME position and orientation from ForeCAT, we then determine the passage of the CME over a simulated spacecraft. We model the CME’s magnetic field using a force-free flux rope and we determine the in situ magnetic profile at the synthetic spacecraft. We show that FIDO can reproduce the general behavior of four observed CMEs. FIDO results are very sensitive to the CME’s position and orientation, and we show that the uncertainty in a CME’s position and orientation from coronagraph images corresponds to a wide range of in situ magnitudes and even polarities. This small range of positions and orientations also includes CMEs that entirely miss the satellite. We show that two derived parameters (the normalized angular distance between the CME nose and satellite position and the angular difference between the CME tilt and the position angle of the satellite with respect to the CME nose) can be used to reliably determine whether an impact or miss occurs. We find that the same criteria separate the impacts and misses for cases representing all four observed CMEs.},
doi = {10.3847/1538-4357/835/2/117},
journal = {Astrophysical Journal},
number = 2,
volume = 835,
place = {United States},
year = {Wed Feb 01 00:00:00 EST 2017},
month = {Wed Feb 01 00:00:00 EST 2017}
}
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