Have you ever asked yourself what causes magnetic forces? Where do magnetic fields come from? How are they related to solar flares, geomagnetic space storms and northern (or southern) lights?
Magnetic forces and fields are nearly everywhere. Of course, in every-day life we are used to fridge magnets, or magnetic clips. However, our computers and phones also rely on magnetic forces.
On a much larger scale we have our own planet, the Earth, that has its own magnetic field that protects us from damaging radiation from the sun. The sun in its turn also has a magnetic field, and so do all the gas clouds in the galaxies.
There are different sources for magnetic fields. Here we look at the main cause for magnetic fields in space since we like to look at solar flares and space storms. The unique thing is that the space magnetic source, as it turns out from recent research, can also “cut” and reconnect magnetic fields. How interesting is that?
Biermann Battery – Plasma Clouds Creating Massive Magnetic Fields
The source of magnetic fields in space clouds – gas clouds or plasma clouds in between stars – is called the Biermann battery. This effect was discovered by the German astrophysicist Ludwig Biermann in 1950.
Basically, the Biermann battery works based on differences in temperature and density of a plasma cloud. Plasma is a mixture of loose electrons and atomic nuclei (atomic nuclei are made up of protons and neutrons). Normally, electrons and atomic nuclei combine to form single atoms, but in plasma it is free for all.
A plasma cloud is never uniform. There is a gradient between high and low temperature, or between a large number of particles in a single volume and a smaller number of particles. As soon as you have such gradients, or potentials, an electric current is formed. Electric currents are responsible for creating magnetic fields.
Magnetic fields you can imagine as bands of parallel strings. At each point in the field, the magnetic pull is in the direction of the string at the same location. These strings are called magnetic lines.
Using computer simulations of this Biermann battery effect, researchers have now discovered a new aspect. At the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL) researchers found out that the Biermann battery can also “cut” through and reconnect magnetic field lines.
When the magnetic field lines are reconnected, a lot of energy is released. Each time this happens a large burst of energy is sent into space.
When the magnetic field lines are reconnected, a lot of energy is released.
This snapping apart and reconnecting of the magnetic field lines causes solar flares, geomagnetic space storms and northern lights. These things can seriously mess with our power grid networks and mobile phone reception.
Read more about how the researchers found out about this reconnection effect here. (external link to the PPPL website)
The Earth’s magnetic field is caused by currents in the molten outer core of the Earth. Other movement inside the Earth – convection in the Earth’s mantle – causes moving plates, earthquakes and tsunamis. Read more here.