Magnetic pulsations

{{short description|Oscillations in a planet's magnetic field}}

Magnetic pulsations are extremely low frequency disturbances in the Earth's magnetosphere driven by its interactions with the solar wind.{{cite web |url=http://roma2.rm.ingv.it/en/themes/22/magnetic_pulsations |title=Magnetic pulsations |access-date=2021-01-20}} These variations in the planet's magnetic field can oscillate for multiple hours when a solar wind driving force strikes a resonance.{{cite web |url=https://spaceweather.com/archive.php?view=1&day=20&month=01&year=2021 |title=A MUSICAL NOTE FROM THE MAGNETOSPHERE |quote=High above the Arctic Circle in Lofoten, Norway, citizen scientist Rob Stammes operates a space weather monitoring station. His sensors detect ground currents, auroras, radio bursts, and disturbances in Earth's magnetic field. Yesterday, he says, "I received a musical note from the magnetosphere."}} This is a form of Kelvin–Helmholtz instability. The intensity, frequency, and orientation of these variations is measured by Intermagnet.

In 1964, the International Association of Geomagnetism and Aeronomy (IAGA) proposed a classification of magnetic pulsations into continuous pulsations (Pc) and irregular pulsations (Pi).{{cite journal |doi=10.1007/s10712-005-1758-7 |author=McPherron, R.L. |title=Magnetic Pulsations: Their Sources and Relation to Solar Wind and Geomagnetic Activity |journal=Surv Geophys |volume=26 |pages=545–592 |year=2005 |issue=5 |bibcode=2005SGeo...26..545M |s2cid=122004707 }}