Collision-Less Shock Waves

Why in News?

Recently researchers have found that Collision-less shock waves could be the cosmic engines driving subatomic particles in space to extreme speeds.

Shock waves – Are waves that can transmit waves at faster than the speed of sound through the atmosphere.
Plasma – The shock waves are born in plasma, a gas of charged particles that can conduct electricity and interact with magnetic fields.
Collision less shock waves – When the solar wind hits Earth's magnetic field, it creates special kinds of shock waves called "collision-less shock waves."
Occurrence – Collision-less shock waves occur throughout the universe including:
- Near pulsars and magnetar
- In accretion disks around black holes
- During supernova explosions
- In interstellar and intergalactic media
Key characteristics – Formation in low-density plasmas where particles rarely collide.
Unlike regular shock waves, Collision less shock waves transmits energy transmission through electromagnetic forces.
Capability to accelerate particles to relativistic speeds (close to light speed).
Natural particle accelerators – The researchers discovered that these shock waves act like natural particle accelerators, capable of boosting electrons to enormous speeds.
Using data from NASA satellites, they observed electrons reaching up to 86% of light speed near Earth.
Electron injection problem – This discovery helps solve what scientists call the "electron injection problem" which explains how electrons get their initial boost before being accelerated to even higher energies in space.

The electron injection problem is the scientific term for the mystery of how electrons gain energy in outer space.

Implications for Cosmic Rays –Cosmic rays could be generated due to similar interaction of planetary electrons (earth magnetosphere particles) with the Stellar winds (similar to solar wind).