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An intercomparison of plasma turbulence at three comets: grigg-skjellerup, giacobini-zinner, and halley
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Glassmeier, K.-H. Tsurutani, Bruce T. Neubauer, F. M. |
| Copyright Year | 1995 |
| Description | We examine and intercompare the LF plasma wave turbulence at three comets: Grigg-Skjellerup (GS), Giacobini-Zinner (GZ), and Halley (H). All three have power spectral peaks at the local ion cyclotron frequency (the pump wave) at approx. 10(exp -2) Hz, and a power-law fall-off at higher frequencies that suggest the development of turbulent cascades. The power laws for the three comets are approximately f(exp -1.9), f(exp -1.9) and f(exp -2.1), respectively. However, other than the similarities in the power spectra, we find the magnetic field turbulence is considerably different at the three comets. Phase steepening is demonstrated to occur at the trailing edges of the GS waves. This is probably due to nonlinear steepening plus dispersion of the left-hand mode components. A coherency analysis of GZ turbulence indicates that it is primarily composed of righthanded mode components, i.e., the turbulence is 'whistlermode.' This too can be explained by nonlinear steepening plus dispersion of the magnetosonic waves. At the level of GS and GZ turbulence development when the spacecraft measurements were made, classical three-wave processes, such as the decay or modulation instabilities do not appear to play important roles. It is most likely that the nonlinear steepening and dispersive time scales are more rapid than three-wave processes, and the latter had not had time to develop for the relatively 'new' turbulence. The wave turbulence at Halley is linearly polarized. The exact nature of this turbulence is still not well understood at this time. Several possibilities are suggested, based on our preliminary analyses. |
| File Size | 390267 |
| Page Count | 4 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19970003423 |
| Archival Resource Key | ark:/13960/t5hb4292m |
| Language | English |
| Publisher Date | 1995-05-01 |
| Access Restriction | Open |
| Subject Keyword | Astrophysics Grigg-skjellerup Comet Magnetometers Plasma Turbulence Power Spectra Giacobini-zinner Comet Comparison Ion Cyclotron Radiation Cyclotron Frequency Magnetic Fields Magnetoacoustic Waves Plasma Waves Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
