Search Publications
Monitoring solar activity on the far side of the sun from sky reflected Lyman α radiation
Bertaux, Jean-Loup; Lallement, Rosine; Schmidt, Walter +3 more
Solar active regions are known to be brighter in Lyman α radiation than the quiet sun. Accordingly, they illuminate more H atoms in interplanetary space through resonance scattering. As we show here, this excess of illumination related to active regions is clearly seen in full-sky Lyman α maps recorded by the SWAN instrument on board SOHO, includi…
Change in photospheric magnetic flux during coronal mass ejections
Gopalswamy, Nat; DeForest, Craig; Lara, Alejandro
We report on the variations of photospheric magnetic flux during coronal mass ejections (CMEs). Using magneograms from the SOHO/MDI instrument, we have computed the magnetic flux of 7 active regions and one disappearing filament region associated with CMEs. When we plotted the flux versus time over a period of few days before, during and after the…
Ulysses observations of the magnetic field structure within CIRs
Forsyth, R. J.; Dunlop, M. W.; Clack, D.
Ulysses encountered two separate sequences of corotating interaction regions (CIRs) in 1992-3 and 1996-7 when the spacecraft was in the southern and northern solar hemispheres, respectively. We have examined magnetometer data from one event observed in each hemisphere. Using two separate analytical methods we provide evidence for the magnetic fiel…
Long-term behavior of Jovian bKOM and nKOM radio emissions observed during the Ulysses-Jupiter encounter
Kaiser, M. L.; Desch, M. D.; Reiner, M. J.
We present observational evidence that the long-term behavior of Jovian bKOM and nKOM radio emissions observed during the Ulysses-Jupiter encounter was controlled by the sector structure of the solar wind. Specifically, we found brightenings in the Jovian bKOM emission, followed by a sudden cessation of the bKOM emission and an onset of an nKOM “e…
Influence of electrophilic species on the lower ionosphere of Titan
Rodrigo, R.; López-Moreno, J. J.; Molina-Cuberos, G. J.
The galactic cosmic rays induced ionosphere of Titan is studied from 0 to 70 km. We resent here a new model developed for calculating the concentration of cations, anions, and electrons depending on the mixing ratio of electrophilic species present in the atmosphere of Titan. The existence of neutral species in which electrons can be attached by t…
Fluctuations of the heliospheric magnetic field and the anisotropy of pickup ions
Balogh, A.; Erdős, G.; Németh, Z.
Pitch angle distribution of interstellar pickup ions at high heliographic latitude is studied. Based on high time resolution magnetic field observations by Ulysses during the south polar pass in 1994, we have determined the angular distribution of particles at the moment of ionization. Due to large deviations of the field from Parker's spiral, it …
Coronal mass ejections detected in solar mean magnetic field
Boberg, Fredrik; Lundstedt, Henrik
One minute resolution solar mean magnetic field sequences during 74 coronal mass ejection events are analyzed using wavelet transforms. A significant fraction of the resulting wavelet power spectra shows a characteristic peak at the time of the coronal mass ejection. With an average period of 13 minutes, the signature in the solar mean field is mo…
Recurrence in MeV proton fluxes and anisotropies at 5 AU from the Sun
Balogh, A.; Dalla, S.
We report the observation of a recurrent pattern in proton fluxes and anisotropies at 5.2 AU from the Sun, made by the Anisotropy Telescopes on board the Ulysses spacecraft between April 1998 and May 1999, during the rising phase of solar cycle 23. The time delay between recurrent features of the pattern is not constant and increases from 122 to 1…