MAGNETOSPHERE
Live Data
A complete list of real-time data links is located in the Space Weather Resources section.
From Satellites: ACE Satellite
The ACE satellite is positioned about 1 million miles from Earth, and is always directly between Earth and the Sun. Since ACE is far outside the Earth's magnetosphere and between Earth and Sun, it is ideally positioned to monitor the speed, composition and magnetic field of the solar wind. The solar wind magnetic field is actually part of the Sun's magnetic field dragged off the surface of the Sun and carried into space. Scientists have discovered that the most intense effects upon Earth's magnetic field occur when the solar wind magnetic field is directed opposite to Earth's magnetic field and the intensity is 'large'. When the solar wind magnetic field is opposite the Earth's, it is called a southward field and is considered to be negative in sign. You will monitor the ACE data to identify times when this happens.
When you open the ACE link, you will see the following screen.
The 'Bz" component is the one that carries information about the North-South part of the solar wind magnetic field. Notice that the second plot from the top in the above image is labeled 'Bz' in yellow. The units used are nano-Teslas (nT), which is a unit of magnetic strength used by scientists. A typical toy magnet has a strength of a million nano-Teslas!
The range of the above image plot is from -6 to +6 nano-Teslas. The scale will vary depending on the strength of Bz, but only rarely does the variation get beyond +40nT or +40nT. The sign of the number, positive or negative, indicates whether it is north-directed (positive) or south-directed (negative).
The amount of disturbance of the Earth's magnetic field is dependent upon several factors ( e.g. a negative Bz, solar wind speed, and duration), however, the best single indicator is the Bz. Remember, the Earth's magnetic field is disturbed the most when the solar wind magnetic field is negative.
We can classify storms as:
- Low if the Bz is between +3 nT and +5 nT,
- Medium if the Bz is between +5 nT and +10nT,
- High if the Bz is +10nT or larger,
- Extreme Some of the most severe storms in the past several years have registered Bz values between +20 and +40 nT!
ACE Bz Archive
When you select the ACE Bz Archive you will be able to search for changes in the magnetic field in space back to 1997. The first page you see will allow you to select the year and the starting date and ending date.
You can do a broad search over a long period of time or narrow your search to only a few days. After you select the time period, click on ‘Retrieve Data’. The plot below shows the magnetic field between May 24 and June 6. There is a large disturbance from May 29 to May 31.
The large, negative magnetic field affected Earth’s magnetic field and caused auroras as far south as Virginia .
ACE Solar Wind Archive
A similar archive is available for ACE Solar Wind. When you select a time range, you will get two plots. One plot shows the speed of the protons in the soalr wind. The second plot shows the density of protons (number of protons per cubic centimeter) in the solar wind. These plots of protons in the solar wind can be useful for more advanced research. High speed, high density solar winds are often the result of coronal mass ejections. Although high speed solar winds can also be due to coronal holes. Coronal mass ejections and coronal holes can cause disturbances to Earth's magnetosphere.
For More ACE data, visit the Real Time Solar Wind website where you will see the page below.
In the left-hand column, click on 'Dynamic Plots'
The right frame will open a window that looks like the image below. At this point you can select the type of data and the time period you wish.
- NASA Official: Dr. James Thieman
- Project Manager: Don Robinson-Boonstra
- Website Manager: Bryan Stephenson