Heavy Ions

The ionosphere is an outer layer of Earth's atmosphere where neutral molecules are ionized by collisions and solar radiation. Close to Earth's magnetic poles, ionospheric ions are uplifted by electric currents and waves and then injected into different regions inside Earth's magnetopause, the frontier between Earth's closed magnetic field lines and the solar wind. The plasma that populate each of these regions have different composition and properties their dynamics are strongly affected by the coupling between the solar wind and the magnetosphere. Among these regions, one of them is particularly relevant for the interaction of Earth's magnetic field with the solar wind, the so called Warm Plasma Cloak (WPC).

The warm plasma cloak is a region of the magnetosphere that partially envelopes an internal layer, the plasmasphere and Earth. It extends from the night side through dawn up to noon, is populated by a warm plasma (compared to the temperature of the plasma in other regions inside the magnetopause) and is made of electrons, protons, and a smaller proportion of ionospheric ions, O+ and He+. The presence of these heavy ions close to the dayside magnetopause, specially O+, affects strongly the [reconnection] of magnetic field lines of the solar wind and Earth's magnetic field. In turn, the presence of O+ in the WPC is related to the entrance of solar wind particles into the interior of the magnetopause, which potentially can damage satellites and electric grids on Earth.

At Heliosphere UM, we aim to find out what are conditions that favor a warm plasma cloak rich in O+ and study the impact of heavy ions on magnetic reconnection at the dayside magnetopause. In order to do so, we use mode than 6 years of data from the Magnetosphere MultiScale (MMS) spacecraft mission to analyze the plasma properties in the magnetosphere and the OMNI database, which contains the plasma properties measured in the solar wind by various spacecrafts at Earth's distance from the Sun.