Plasma is the fourth state of matter after solid, liquid, and gas. Essentially, plasma is a gas that’s so hot the atoms are separated into electrons and ions. Because the parts of the atoms can move independently of each other, plasma is electrically charged and responds to electromagnetic fields and forces. As a result of its magnetization, plasma interacts with the magnetic fields of space in interesting ways. For example, the process of magnetic reconnection explains changes in the polarity of the magnetic fields of plasma.

Magnetic Reconnection

Plasma contained within a magnetic field in space frequently comes across other plasma. If the plasmas have oppositely polarized magnetic fields, they can still interact through a process called magnetic reconnection. According to observations of space, magnetic reconnection occurs when two plasmas are only separated by a weaker magnetic field. The plasmas’ magnetic fields, despite having opposite polarization, will come together and cancel out the magnetic flux. The oppositely polarized magnetic fields are able to reconnect when the dominant particles of a plasma are accelerated enough to break magnetic field lines. In this process, the magnetic energy of the magnetic fields is converted to kinetic and heat energy.

As a result of the energy conversion, the plasma shoots out along the weaker field and a new magnetic structure forms from the reconnected magnetic field lines. The magnetic reconnection process results in space phenomena such as solar flares and coronal mass ejections when it occurs on the Sun. Reconnection can also occur within Earth’s magnetosphere but researchers usually study the process by recreating it in laboratories. Recently, NASA launched the Magnetospheric Multiscale (MMS) mission to study magnetic reconnection a little more closely. The mission will orbit Earth and pass through regions where magnetic reconnection occurs frequently.

Magnetization of space plasma is a fascinating field that requires further study. For more information about magnetic reconnection, follow the updates for the MMS mission.

Image by NASA Goddard Space Flight Center