Space weather and current solar wind data by ACE

The ACE space laboratory studies the energy particles of the solar wind or the space weather.

Solar wind density

Number of protons from the solar wind per unit volume measured by ACE through SWEPAM. (Measured)

Solar wind speed

Average speed of protons from the solar wind measured by ACE/SWEPAM. Same as the speed of air molecules, known as "wind speed" of the Earth surface. (Measured)

Solar wind pressure

Hydraulic pressure of the solar wind is the force per unit area required to stop the solar wind flow. This is similar in concept to the force a surface wind exerts on a sail. The solar wind ram pressure depends on the solar wind speed and density. (Derived)

Solar wind temperature

The temperature of protons in the solar wind. It is measured by ACE/SWEPAM.(Measured)

Interplanetary magnetic field magnitude

The strength of the interplanetary magnetic field (IMF) as measured by the ACE Magnetometer (MAG). (Measured)

Interplanetary magnetic field polar angle

The angle between the IMF and the geomagnetic axis. When the IMF is southward, antiparallel fields near the magnetospheric subsolar point allow merging between the IMF and geomagnetic fields. This process increases the transport of solar wind mass, momentum, and energy into the Earth's magnetosphere. This process can also open the magnetosphere to solar energetic particle radiation. In severe conditions this radiation can threaten high altitude aircraft in high latitude and polar regions. Under less severe conditions this radiation can still threaten polar orbiting spacecraft. This quantity depends on IMF components measured by ACE/MAG. (Derived)

Interplanetary magnetic field azimuth

The direction of the IMF perpendicular to the geomagnetic axis. This affects the details of solar wind-magnetosphere interactions; however, this is of tertiary importance compared to the IMF magnitude and polar angle. This quantity also depends on IMF components measured by ACE/MAG. (Derived)

Voltage across the polar cap and convection potential

The solar wind energy input to the magnetosphere that drives magnetospheric convection. It appears as an electric potential imposed across the polar ionosphere. The quantity shown here is an estimate of the asymptotic convection potential based on ACE/SWEPAM and ACE/MAG measurements as well as the work of Boyle, et al. (Journal of Geophysical Research 102, 111, 1997.) This estimate is asymptotic because it does not account for the time delays such as those imposed by friction between the ionosphere and the neutral atmosphere.