When magnetic reconnection happens tremendous bursts of energy can be released, which can be equivalent to the explosive force of billions of megatons of TNT, as well as sending particles hurtling through space at speeds close to that of light itself. Powerful reconnection events are capable of disrupting modern technology, such as power grids. It is also related to the beautiful phenomenon that can be seen at the Earth’s poles; the Aurora.
But what exactly is magnetic reconnection? It occurs when oppositely directed magnetic field lines break and reconnect in a plasma (the fourth state of matter that is thought to make up over 99% of matter in the Universe, made up of separated positive ions and negative electrons). While the process is not yet fully understood, scientists are optimistic that the new NASA program will make great forward strides in the field.
An infinitely conductive plasma locks in the magnetic field lines, whilst the field lines cause the charged particles in the plasma to be fixed in circular orbits around the field lines. This means that these plasmas will not diffuse across field lines and mix, whilst two separate field lines will never mix, as they cannot penetrate the plasma, which effectively forms a barrier between the magnetic field lines. However, this must not be the case, as observations have shown that the plasmas do in fact mix.
This apparent contradiction between observation and theory, which normally means an overhaul of the way we think about something, can be resolved when another fact is added to the equation: when plasmas orbiting oppositely directed magnetic field lines are brought together, a strong current sheet is produced. This non-physical current sheet, along with the presence of even an exceptionally tiny amount of resistance, allows the plasma to diffuse across the field line. In turn, this means that the field lines can break and reconnect – magnetic reconnection.