[Everyone] Space Physics Seminar, Friday May 30th: Growth and evolution of EMIC waves in the Earth’s magnetosphere (J.H. Lee, UCLA EPSS & IGPP)

[Emmanuel V. Masongsong]

SPACE PHYSICS SEMINAR 

DEPARTMENT OF EARTH, PLANETARY AND SPACE SCIENCES 

DEPARTMENT OF ATMOSPHERIC AND OCEANIC SCIENCES 

UNIVERSITY OF CALIFORNIA, LOS ANGELES 

(EPSS M288A, AOS M275A ) 







Justin H. Lee 


UCLA EPSS & IGPP 





Growth and evolution of electromagnetic ion cyclotron waves in the presence of multiple ion species in the Earth’s magnetosphere 








Abstract: 


Although it is well known that the generation and properties of EMIC waves are strongly affected by the abundance of heavy (He + and O + ) ions relative to the cold protons and hot proton free energy, only recently have we investigated through linear warm plasma theory additional effects of low-energy (few to 100s eV) heavy ion temperature that cause the wave properties to evolve from the classical cold plasma description. I will describe how fortuitous observations of multiple ion species—with the compositional properties (partial densities and temperatures) of the usually invisible low-energy protons and He + —and EMIC waves obtained from multi-instrument measurements made by one of the NASA THEMIS spacecraft, when combined with linear warm plasma theory, provide a detailed and consistent description of the waves. These observations of the low-energy ions motivate a multi-spacecraft statistical study to characterize the presence and typical compositional properties of low-energy ions, essential for improving our understanding of EMIC waves that have also been observed throughout the Earth’s magnetosphere. In my application of the techniques to deduce the low-energy ion properties and the knowledge gained from the statistics to observations and modeling of typical EMIC waves as function of local time, I am able to successfully explain the growth and properties of these waves. The results of this investigation imply that both the densities and temperatures of the low-energy ions need to be considered in addition to the hot protons for future EMIC wave studies and in particular for further understanding of why recent observational studies have found that the waves may only scatter relativistic radiation belt electrons in the >2 MeV range. 




Friday, May 30, 2014 

Room 6704 Geology 

3:30 - 5:00 PM 



Refreshments served after the seminar in Room 6850. 



In-Charge 
V. Angelopoulos 

X.-Z. Zhou 
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