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Instructor: Gregory Fleishman

Physics 777 Plasma Physics and Magnetohydrodynamics (MHD). Low-frequency radiation of the Galaxy. Instructor: Gregory Fleishman. F. Urtyev. 9 December 200 8. Study of the galactic low-frequency radiation. ( The Explorer 43 ). ULYSSES. IMP-6 91 m dipole antenna Date of launch: 1971.

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Instructor: Gregory Fleishman

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  1. Physics 777Plasma Physics and Magnetohydrodynamics (MHD) Low-frequency radiation of the Galaxy Instructor: Gregory Fleishman F. Urtyev 9 December 2008

  2. Study of the galactic low-frequency radiation (The Explorer 43) ULYSSES IMP-6 91 m dipole antenna Date of launch: 1971 WAVES 100 m dipole antenna Date of launch: 1994 ULYSSES 72 m dipole antenna Date of launch: 1994

  3. Spectrum of the low-frequency galactic radiation Intensity Index of modulation [] – ISEE-3 (and ◊) O – Ulysses (Hoang) * - Brown (IMP-6) Tokarev et al, 2000 Dulk et al., 2001

  4. Emissivity • hot phase ISM component (ne=3*10-3 cm-3, T=104 K, B=3*10-6 G) • warm phase ISM component (ne=3*10-2 cm-3, T=106 K , B=3*10-6 G) • local cloud component near the Earth (ne=3*10-1 cm-3, T=7000K , B=3*10-6 G) α – filling factor τ – optical depth ε – emisivity k – coefficient of absorption

  5. Emissivity of Interstellar medium

  6. Emissivity of Interstellar medium

  7. Emissivity of Interstellar medium

  8. Absorption • warm phase ISM component (ne=0.05 cm-3, T=5*103 K, Leff=0.5 kpc, • filling factor α=50%) • Reynolds clouds (zones of H II with low surface brightness) • ne=0.2 cm-3, T=104 K, l=30-50 pc, filling factor α=20-50% • local cloud component near the Earth (ne=3*10-1 cm-3, T=7000K , B=3*10-6 G)

  9. T=20000 K

  10. Low-frequency background radiation spectra Reynolds clouds ne=0.2 cm-3, T=2*104 K, l=40 pc, filling factor α=20 % • hot ISM ne=3*10-3 cm-3, T=104 K, B=3*10-6 G • warm ISM ne=3*10-2 cm-3, T=106 K • local cloud ne=3*10-1 cm-3, T=7000K

  11. Anisotropy

  12. Anisotropy

  13. Conclusion? • Processes of radiation and propagation for low-frequency emission of the Galaxy significantly interact with surrounding medium • Direct modeling of sources for this radiation will be able not only predict distribution of charged particles and spatial structure of magnetic fields in source but also will help to estimate parameters of different components of interstellar medium (density, temperature, filling factors) • It could also help to check available models of ISM to ability for adequately description of observational data

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