Solar Wind Speed
Updates: every 10 minutes
Last updated 18 May 2008 10:07 UT
| Solar Wind Parameters Used:
Date: 18 05 2008 1004 UT
Velocity: 352 km/sec
Bz: -2.0 nT
Density = 7.0 p/cc
Calculated Information from Solar wind parameters:
Magnetopause Stand Off Distance = 11.8Re
Solar Wind Dynamic Pressure Dp = 0.72nPa
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This diagram indicates the i) solar wind speed and ii) strength of the interplanetary
magnetic field (IMF) in a north/south direction. Higher solar wind speeds and strong
south pointing (negative) IMF are associated with geomagnetic storms on earth. The
red area on the image indicates an approximate region in which disturbed conditions
might be expected.
The plots on this page were produced from data supplied by the NOAA Space Environment
Center. This Real Time Solar Wind (RTSW) data set originates from NASA's Advanced
Composition Explorer (ACE) satellite. The above image shows with a black square the
value of the solar wind speed (horizontal) axis and the strength of the interplanetary
magnetic field in a north/south direction (Bz - vertical axis). Higher solar wind speeds
and strong south pointing (negative) interplanetary magnetic field are associated with
geomagnetic disturbances on earth. The red area on the image indicates an approximate
region in which disturbed conditions might be expected. The coloured dot within the black
square, is an indicator of solar wind density, and is yellow when density exceeds 5 particles
per cubic cm, red when density exceeds 10 particles per cubic cm, otherwise green.
The ACE spacecraft is positioned at the L1 point between the Earth and the sun and
gives approximately one hour advance notice of conditions on Earth.
The image below shows recent trends in solar wind speed and interplanetary magnetic
field north/south direction.
Solar Wind Model Driven by ACE data
IPS is running an ACE data driven model of the solar wind each day in the Australian Space Forecast Centre.
The model output displays a complete solar rotation of several solar wind parameters, over the last 27 days.
You can view the solar wind model ouput image here.This solar wind model updates daily and is driven by the US ACE (Advanced Composition Explorer) satellite. Longer lived structures in the solar wind, like coronal hole high speed wind streams, are visible in the "Velocity" plot as a fan like structure of greater than average velocity. As you move around the circular plot you are going from one day to the next, with the Earth on the circumference of the circle and the Sun in the centre, with the numbers 1,2 giving the first day of the rotation and the sense of direction.
Application:Using 27 day persistance, which is the average solar roatation period, IPS forecasters can use this information to anticipate the arrival of the coronal hole high speed stream, and warn its customers of the expected disturbance.
Reference Florens, "M. S. L., Cairns, S. A. Knock, and P. A. Robinson (2007), Data-driven solar wind model and prediction of type II bursts, Geophys. Res. Lett., 34, L04104, doi:10.1029/2006GL028522".
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Solar