Strahl, from the German for "ray" or "beam" such as radiation is, is the

electron The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no ...

component of the

solar wind The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma mostly consists of electrons, protons and alpha particles with kinetic energy between . The composition of the sol ...

that is the most closely aligned with the magnetic field of the

Sun The Sun is the star at the center of the Solar System. It is a nearly perfect ball of hot plasma, heated to incandescence by nuclear fusion reactions in its core. The Sun radiates this energy mainly as light, ultraviolet, and infrared radi ...

. These electrons are part of the high speed component of the solar wind and have sufficient velocity to escape from the electrostatic potential of the Sun. They carry the electron heat flux of the solar wind and always move away from the Sun along the magnetic field lines. Strahl are distinguished from the 'core' and 'halo' populations of electrons, which form part of the low and high speed solar winds and are normally anisotropic with respect to the Sun's magnetic field. Electrons precipitating into the polar regions of the Sun form the source of the strahl. When the magnetic lines of force are connected with the interplanetary magnetic field (IMF) in the appropriate direction, the strahl electrons are transported from the solar corona with energies of up to several hundred eV. When the Sun's magnetic field lines are not connected with the IMF, the strahl effect is blocked at that pole.

References

Solar phenomena Space plasmas {{sun-stub