Wave particle interplay in planetary magnetospheres - case studies from Earth and Jupiter

At altitudes above the atmosphere of a planet, space is filled with plasma, which is a gas of electrons and ions. These charged particles move in an ordered way under the influence of the magnetic field of the planet. There are also electromagnetic waves (oscillations) in plasma similar to wind waves (mechanical) in water in these regions (magnetospheres). The coexisting waves and particles strongly interact with one another when their rhythmic movements are synchronized – like a coordinated push to the child’s playground swing. As the child’s swing could gain/lose energy from the matched action by the parent, charged particles could gain/lose energy from the electromagnetic waves. This is wave-particle interaction. There are many varieties of wave-particle interactions going on in planetary magnetospheres. In this thesis, I studied three interactions – two in the Earth’s magnetosphere and one in Jupiter’s magnetosphere. In the first study, I found that the nominal boundary of the Earth’s radiation belt was broken when a certain type of (ultra-low frequency-ULF) wave was present. In the second study, I found how the presence of another kind of (magnetosonic) wave favored the existence of particles with a certain orientation (pitch angle). In the third study, I documented the occurrence regions of yet another kind of (electron cyclotron harmonic-ECH) wave in Jupiter’s magnetosphere. I found that it is quite different from Earth and recorded how Jupiter’s volcanic moon Io may alter the generation region of these waves. I also worked on the development of a UIowa-led particle instrument, which was launched on a rocket in March 2022.