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[en] Fast mode magnetosonic waves are typically confined close to the magnetic equator and exhibit harmonic structures at multiples of the local, equatorial proton cyclotron frequency. Here, we report observations of magnetosonic waves well off the equator at geomagnetic latitudes from -16.5°to -17.9° and L shell ~2.7–4.6. The observed waves exhibit discrete spectral structures with multiple frequency spacings. The predominant frequency spacings are ~6 and 9 Hz, neither of which is equal to the local proton cyclotron frequency. Backward ray tracing simulations show that the feature of multiple frequency spacings is caused by propagation from two spatially narrow equatorial source regions located at L ≈ 4.2 and 3.7. The equatorial proton cyclotron frequencies at those two locations match the two observed frequency spacings. Finally, our analysis provides the first observations of the harmonic nature of magnetosonic waves well away from the equatorial region and suggests that the propagation from multiple equatorial sources contributes to these off-equatorial magnetosonic emissions with varying frequency spacings.
[en] The SMILETRAP experimental set-up, a Penning trap mass spectrometer for highly charged ions, is described. Capture and observation of cyclotron frequencies of externally produced highly charged ions, rapid interchange of investigated and reference ions and measurements of the rotational kinetic energies are demonstrated. Mass measurements utilizing different charge states and species to verify the consistency of the measurements are presented. A relative uncertainty of about 10-9 is attained in comparisons between highly charged carbon, nitrogen, oxygen, neon and the singly charged hydrogen molecule
[en] Extended observations of auroral roar, a weak radio emission near the second harmonic of the electron cyclotron frequency, are reported. A total of 69 events were recorded and analyzed. Data for frequency band, duration, and local time of occurrence are presented. The height of the generation region is estimated to be 275-575 km
[en] Complete text of publication follows. The passage of the Cluster satellites in a polar orbit through Earth's magnetotail has provided numerous observations of harmonically related Pc 1-2 ULF wave events, with the fundamental near the local proton cyclotron frequency. Broughton et al. [JGR 2008] reported observations by Cluster of three such events in the plasma sheet boundary layer, and used the wave telescope technique to determine wave propagation nearly perpendicular to B0. We report here on a survey of the entire set of Cluster observations in Earth's magnetotail during 2003: 34 harmonically related wave events were observed during 13 of the 42 tail passes of Cluster from July 22 to October 28. Event durations were commonly < 5 min, but ranged up to 40 min. Wave events were distributed rather evenly from -7 RE out to the Cluster apogee distance of -18 RE, with one event also observed at X = -4 RE. The distribution in the YGSE coordinate was also rather even but asymmetric, between -9 and + 17 RE. Events occurred for ZGSE values from -10 to -3 RE and +3 to +7 RE; i.e., none was observed for |Z| < 3 RE. Each wave event was associated with signatures of the PSBL in the CIS instrument: elevated fluxes of ions with energies from 1 keV to over 30 keV, and highly variable, often counterstreaming ion velocities.
[en] A method is suggested of measuring cyclotron frequency of ions with different mass-to-charge ratios. The method involves production of ions in the source with an electron impact of the magnetic resonance mass-spectrometer, acceleration of ions by the electric field, amplitude modulation of their energy, indication of output current of the resonance ions and determination of frequency of the cyclotron ion resonance as per peak current. Transition from recording ions with a certain mass-to-charge ratio to that with some other ratio is performed through variation of frequency and amplitude of the modulating voltage
[en] Complete text of publication follows. Applying a strong uniform magnetic field onto a strongly coupled plasma gives rise to a number of interesting and peculiar effects. Here, we report on two of these: The effect of a magnetic field on the wave spectra of strongly coupled 2D systems and the influence of a magnetic field on field-parallel and cross-field diffusion in 3D systems. The magnetized 2D one-component plasma sustains two modes, the magnetoplasmon and the magnetophonon, the frequencies of which are of the order of the Einstein or cyclotron frequency. We report on the existence of additional high-frequency plasma oscillations in Coulomb and Yukawa systems at multiples of the magnetoplasmon, based on extensive molecular dynamics simulations. The emergent modes are reminiscent of the well-known Bernstein modes but are renormalized by the strong interparticle correlations. We present detailed numerical results and an analytical description of the observed features. The diffusion coefficient of magnetized 3D plasma has been studied thoroughly in the weak-coupling regime, both experimentally and theoretically. Much less is known about the strong-coupling regime, where the diffusion coefficient parallel to the magnetic field is also affected. Simulation results in this regime are presented and the scaling of the diffusion coefficient with the magnetic field are discussed.