PLASMA and Sound
There is a similarity between plasma and sound. Plasma and sound can be interchangeable. Plasma is the most abundant material in the universe. A large variety of waves exist in plasma [Space Physics/MB Kallenrode].
Magnetohydrodynamic Waves: Magnetohydrodynamic waves are low-frequency waves related to the motion of the plasma’s ion component. They can be understood intuitively from the concepts of magnetic pressure and magnetic tension. In a magneto-sonic wave, compression of field lines creates a magnetic pressure pulse, which propagates perpendicular to the field in the same way an ordinary pressure pulse propagates through a gas in a sound wave.
…the maximum speed of a disturbance propagating along the magnetic field can be compared with the speed of sound in a gas.
Magneto-Sonic Waves: A magneto-sonic wave is similar to a sound wave: it is a longitudinal wave parallel to the magnetic field with alternating regions of compression and rarefaction (rarefied/lessening of density) in both the plasma and in the magnetic field.
Ion-Acoustic Waves: Sound waves are pressure waves. They transport momentum from one layer to the next due to collisions between molecules and atoms. Despite its often low-density, in a plasma a similar phenomenon exists.
These are some of Professor Don Gurnett’s favorite sounds of space, recorded by University of Iowa instruments on a variety of spacecraft over the past 50 years.
Listen to the EarthWhistlers, especially the Earth Proton Whistlers:
The sounds of interstellar space
November 4, 2013 by Dr. Tony Phillips
Fried Sky (below) on the Olympic Peninsula (photo enhanced by me)
Pacific Ocean: Northern Hemisphere, in the middle & west of USA (below) http://go.nasa.gov/2g5KVuo
South of Aleutian Islands (below) http://go.nasa.gov/2g5NFrS
Chukchi Sea / Alaska Arctic (below) http://go.nasa.gov/2g5kdEC
North of Antarctica & south of Australia (below) http://go.nasa.gov/2g5Ld4I
Japan & Hokkaido (below) http://go.nasa.gov/2g5Sgdp
USA middle eastern states (below) / Nov. 18, 2016 http://go.nasa.gov/2g5QPvt
East coast Newfoundland & Labrador / Nov. 18, 2016