Search Publications
Empirical Modeling of the Quiet and Storm Time Geosynchronous Magnetic Field
Tsyganenko, N. A.; Andreeva, V. A.
A dynamical empirical model of the near-geosynchronous magnetic field has been constructed, based on a recently developed radial basis functions approach and a multiyear set of spacecraft data taken by Time History of Events and Macroscale Interactions during Substorms (THEMIS), Polar, Cluster, and Van Allen Probes missions including 133 geomagnet…
Solar EUV Flux Proxy Using Multifrequency Solar Radio Flux
Zhang, Yongliang; Paxton, Larry J.
We report a new solar extreme ultraviolet (EUV; 26-34 nm) proxy using solar radio fluxes at six different frequencies (410; 610; 1,415; 2,695; 4,995; and 8,800 MHz) from ground-based observations. The radio fluxes (2002-2008) are used to estimate the solar EUV flux under nonsolar flare conditions through an artificial neural network trained with c…
Statistical Similarities Between WSA-ENLIL+Cone Model and MAVEN in Situ Observations From November 2014 to March 2016
Baker, D. N.; Halekas, J. S.; Lee, C. O. +4 more
Normal solar wind flows and intense solar transient events interact directly with the upper Martian atmosphere due to the absence of an intrinsic global planetary magnetic field. Since the launch of the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, there are now new means to directly observe solar wind parameters at the planet's orbital …
Solar Sources of Interplanetary Magnetic Clouds Leading to Helicity Prediction
Riley, Pete; Ulrich, Roger K.; Tran, T.
This study identifies the solar origins of magnetic clouds that are observed at 1 AU and predicts the helical handedness of these clouds from the solar surface magnetic fields. We started with the magnetic clouds listed by the Magnetic Field Investigation (MFI) team supporting NASA's Wind spacecraft in what is known as the MFI table and worked bac…
Modeling observations of solar coronal mass ejections with heliospheric imagers verified with the Heliophysics System Observatory
Rodriguez, L.; Zhang, T. L.; Möstl, C. +19 more
We present an advance toward accurately predicting the arrivals of coronal mass ejections (CMEs) at the terrestrial planets, including Earth. For the first time, we are able to assess a CME prediction model using data over two thirds of a solar cycle of observations with the Heliophysics System Observatory. We validate modeling results of 1337 CME…
Modeling solar energetic particle events using ENLIL heliosphere simulations
Futaana, Y.; Luhmann, J. G.; Odstrcil, D. +9 more
Solar energetic particle (SEP) event modeling has gained renewed attention in part because of the availability of a decade of multipoint measurements from STEREO and L1 spacecraft at 1 AU. These observations are coupled with improving simulations of the geometry and strength of heliospheric shocks obtained by using coronagraph images to send erupt…
Solar energetic particle warnings from a coronagraph
St. Cyr, O. C.; Burkepile, J. T.; Posner, A.
We report here the concept of using near-real time observations from a coronagraph to provide early warning of a fast coronal mass ejection (CME) and the possible onset of a solar energetic particle (SEP) event. The 1 January 2016, fast CME, and its associated SEP event are cited as an example. The CME was detected by the ground-based K-Cor corona…
SPRINTS: A Framework for Solar-Driven Event Forecasting and Research
Falconer, D. A.; Engell, A. J.; Schuh, M. +2 more
Capabilities to predict onset and time profiles of solar-driven events, including solar X-ray flares; solar energetic particles (SEP); coronal mass ejections; and high-speed streams, are critical in mitigating their potential impacts. We introduce the Space Radiation Intelligence System (SPRINTS). This NASA-invested technology integrates preerupti…
Predicting the magnetic vectors within coronal mass ejections arriving at Earth: 2. Geomagnetic response
Thompson, B. J.; Bothmer, V.; Richardson, I. G. +6 more
This is a companion to Savani et al. (2015) that discussed how a first-order prediction of the internal magnetic field of a coronal mass ejection (CME) may be made from observations of its initial state at the Sun for space weather forecasting purposes (Bothmer-Schwenn scheme (BSS) model). For eight CME events, we investigate how uncertainties in …
Seismic imaging of the Sun's far hemisphere and its applications in space weather forecasting
Lindsey, Charles; Braun, Douglas
The interior of the Sun is filled acoustic waves with periods of about 5 min. These waves, called "p modes," are understood to be excited by convection in a thin layer beneath the Sun's surface. The p modes cause seismic ripples, which we call "the solar oscillations." Helioseismic observatories use Doppler observations to map these oscillations, …