Solar Wind Data
Solar Wind data are courtesy of OMNI (https://omniweb.sci.gsfc.nasa.gov/ow_min.html), Dr. Natalia Papitashvili, Mail Code 672, NASA/Goddard Space Flight Center, Greenbelt, MD 20771. SuperMAG use the high-time resolution dataset that are “1-min-averaged, field/plasma data sets shifted to the Earth's bow shock nose (BSN). This "High Resolution OMNI" (HRO) data set involves an interspersal of BSN-shifted ACE, Wind, IMP 8 and Geotail data. The following material describes the content and building of this HRO data set and related data sets.”
Data are the "modified" version and have been obtained from: https://spdf.gsfc.nasa.gov/pub/data/omni/high_res_omni/modified/. Time period covered by "modified" 1-min OMNI data is 1995-present. Prior to 1995 we include the 1-min OMNI data. A description of the "modified" data can be found at https://omniweb.gsfc.nasa.gov/form/omni_min_def.html and https://spdf.gsfc.nasa.gov/pub/data/omni/high_res_omni/modified/00readme_modified.
If used in publications and/or presentations please fully acknowledge OMNI: https://omniweb.sci.gsfc.nasa.gov/html/citing.html
Data gaps are indicated by 999999.
Clock angle:
where 
is the interplanetary
magnetic field y and z component (GSM coordinates). Units are degrees.
The Epsilon Parameter:
where
is the clock angle, 
is the solar wind speed, and 
. Units are GW.
The Newell Coupling Function:
where
is the clock angle, is the solar wind speed, and 
is the interplanetary field
magnitude. Units are Wb/s. The original function has been converted to Wb/s by multiplying by CMP = 100 to convert the units to Wb/s (based on the observational estimate made by Cai and Clauer [2013]).
Dynamic Pressure:
where 
is
the mass density. We assume charge neutrality and that the ions and electrons
have identical flow velocities. Further assuming that the ions in the solar
wind consist of 96% H+ and 4% He++ ions. Hence for 1000 electrons there are
923 protons and 77 He ions. Units are nPa.
Akasofu, S.-I. (1981) Energy coupling between the solar wind and the magneto- sphere, Space Sci. Rev., 28, 121.
Cai, X., and Clauer C. R. (2013), Magnetospheric sawtooth events during the solar cycle 23, J. Geophys. Res.: Space Physics, 118, 6378-6388, doi:10.1002/2013JA018819.
Newell, P. T., T. Sotirelis, K. Liou, C.-I. Meng, and F. J. Rich (2007), A nearly universal solar wind-magnetosphere coupling function inferred from 10 magnetospheric state variables, J. Geophys. Res., 112, A01206, doi:10.1029/2006JA012015.
Perreault, P., and S.-I. Akasofu (1978), A study of geomagnetic storms, Geophys. J. R. Astron. Soc., 54, 547–573.
Weimer, D.R., D.M. Ober, N.C. Maynard, M.R. Collier, D.J. McComas, N.F. Ness, C.W. Smith, and J. Watermann (2003), Predicting interplanetary magnetic field (IMF) propagation delay times using the minimum variance technique, J. Geophys. Res., 108, doi:10.1029/2002JA009405.
Weimer, D. R. (2004), Correction to ''Predicting interplanetary magnetic field (IMF) propagation delay times using the minimum variance technique’', J. Geophys. Res., 109, A12104, doi:10.1029/2004JA010691.