Pc5 waves generated by substorm injection: a case study

Abstract

Abstract. We analyzed the spectral-polarized characteristics of Pc5 ULF waves observed on 17 September 2000 after the 03:20:25 UT substorm onset with the satellites GOES 8 and 10 located east and west of the onset location. In the course of the event, the wave polarization changed from mixed (between toroidal and poloidal) to poloidal, and then to mixed again. The hodogram of magnetic field oscillations rotated counterclockwise at GOES 8, and clockwise at GOES 10. It is suggested that the satellites detected the waves generated by the substorm injected clouds of the charged particles drifting in the magnetosphere in the opposite azimuthal directions: GOES 8 (located east of the substorm onset) detected the wave generated by an electron cloud, and GOES 10 (west of the onset) detected the wave generated by a positive ion cloud. This interpretation is confirmed by the energetic particles data recorded by LANL satellites.

Giant pulsations as modes of a transverse Alfvénic resonator on the plasmapause

“…Other analogies include the Kelvin ship waves and lee (mountain) waves in the atmosphere. This approach avoids some difficulties of the instability theory and has a firm observational basis (Zolotukhina et al, 2008;Mager et al, 2009a;Yeoman et al, 2010Yeoman et al, , 2012. Several cases were observed when the giant pulsations appeared at some azimuthal location at the same time as did a cloud of particles injected during substorm arrival at the same spot (Chisham et al, 1992;Wright et al, 2001).…”

Intermediate-<I>m</I> ULF waves generated by substorm injection: a case study

“…The data can be interpreted in terms of the theory of the wave generation by substorm injected particles as elaborated by Mager and Klimushkin (2008), Mager et al (2009) and Zolotukhina et al (2008), with, in this case an electron cloud of energy ∼33 keV acting as the wave source. According to the theory, wave comes into being with mixed polarization.…”

“…The wave activity is interpreted as being stimulated by recently-injected energetic particles. Specifically the wave is thought to arise from an eastward drifting cloud of energetic electrons in a similar fashion to recent theoretical suggestions Zolotukhina et al, 2008;Mager et al, 2009). The azimuthal wave number m is determined by the wave eigenfrequency and the drift velocity of the source particle population.…”

“…The theory of the generation of this mode by substorm injected particles has been elaborated by Mager and Klimushkin (2008) and Mager et al (2009). Although that theory was developed for the proton-driven high-m wave case, its qualitative features can be generalized for a more general situation, with lower m-numbers and a wave source in the energetic electron population (see Zolotukhina et al, 2008).…”

Spatio-temporal structure of Alfvén waves excited by a sudden impulse localized on an L-shell

“…Furthermore, such sources should be moving in the azimuthal direction as they are related to magnetosheath flow, therefore the wave energy finally leaves the system. Klimushkin (2007, 2008), Zolotukhina et al (2008) and Yeoman et al (2012) considered ULF wave excitation by a moving source, but they supposed the source to be widely distributed across magnetic shells while localized in azimuth. A more general theoretical treatment is required here and will be the subject of future studies.…”