The thriller of how the solar’s corona, which is its outer ambiance, reaches tens of millions of levels might have a shocking clarification: cosmic mud using the magnetic waves carrying plasma on the photo voltaic wind.
“For many years, researchers have targeted primarily on how electrons, ions, magnetic fields and plasma waves transport and dissipate vitality within the photo voltaic ambiance,” stated lead researcher Syed Ayaz of the College of Alabama in Huntsville in a statement. “Our work provides a brand new ingredient to this image: mud grains.”
Parker does not carry a cosmic dust detector, and that’s because until now dust has not been considered a serious component of the solar atmosphere. Indeed, in the high temperatures of the solar corona it had been thought that dust could not survive for very long and would therefore have no impact.
However, Parker does host a bunch of antennas and magnetometers collectively referred to as the FIELDS experiment, designed to measure the electromagnetic field and radio emissions in the solar corona. The antennas kept picking up unexpected spikes in voltage, which according to Ayaz and his team are produced by clouds of charged particles created when tiny dust grains slam into Parker at high velocity.
These dust grains have accrued an electrostatic charge, which can interact with the electromagnetic field carried by the solar wind as it leaves the sun, which in turn can influence waves of plasma reverberating through that electromagnetic field called Alfvén waves.
There are two possible, competing ways in which dust can affect the Alfvén waves, which in turn could determine how energy is dumped into the corona, heating it. On one hand, the mass of the dust can act to provide extra inertia to the plasma as it rides the solar wind, allowing the plasma energy to be transported across wider distances. On the other hand, the electric charge on the dust grains can bolster the interactions between charged particles in the plasma, the Alfvén waves and the solar electromagnetic field.
“If dust mass dominates, [Alfvén] wave energy may travel farther into the corona,” said Ayaz. “If dust-charge effects dominate, the energy may be released more locally as particle heating.”
The balance between these two effects can therefore control where and when energy is deposited into the corona, focusing it in areas and causing temperatures there to rise dramatically.
Future solar missions are now going to have to start taking dust into account, said Ayaz, with dedicated detectors designed to measure dust’s properties close to the Sun.
“The bigger question is fascinating,” said Ayaz. “Is dust simply passing through the near-Sun environment, or is it helping shape how electromagnetic energy becomes heat and solar-wind motion?”
The new discovery was reported on July 1 in The Astrophysical Journal.
