Search Publications
Response of the low ionosphere to X-ray and Lyman-α solar flare emissions
Dammasch, Ingolf E.; Kretzschmar, Matthieu; Raulin, Jean-Pierre +4 more
Using soft X-ray measurements from detectors onboard the Geostationary Operational Environmental Satellite (GOES) and simultaneous high-cadence Lyman-α observations from the Large Yield Radiometer (LYRA) onboard the Project for On-Board Autonomy 2 (PROBA2) ESA spacecraft, we study the response of the lower part of the ionosphere, the D region, to …
Electric structure of dipolarization fronts associated with interchange instability in the magnetotail
Zhang, T. L.; Nakamura, R.; Cao, J. B. +6 more
electric structure of dipolarization fronts (DFs) is very important to both DF dynamics and particle acceleration. We performed two-dimensional Hall MHD simulation to study the electric structure of DF produced by interchange instability on the scale of ion inertial length in the flow braking region of near-Earth tail. The results indicate that th…
Quasiperiodic emissions observed by the Cluster spacecraft and their association with ULF magnetic pulsations
Pickett, J. S.; Santolík, O.; Parrot, M. +2 more
Quasiperiodic (QP) emissions are electromagnetic waves at frequencies of about 0.5-4 kHz characterized by a periodic time modulation of the wave intensity, with a typical modulation period on the order of minutes. We present results of a survey of QP emissions observed by the Wide-Band Data (WBD) instruments on board the Cluster spacecraft. All WB…
Venus ion outflow estimates at solar minimum: Influence of reference frames and disturbed solar wind conditions
Barabash, S.; Zhang, T. L.; Nilsson, H. +2 more
Recent estimates of ion escape rates from Venus, based on ASPERA-4 data, differ by more than a factor of 4. Whereas the ASPERA-4 instrument provides state-of-the art observations, the limited field of view of the instrument and the strongly limited geographical coverage of the spacecraft orbit means that significant assumptions must be used in the…
Long-term modulations of Saturn's auroral radio emissions by the solar wind and seasonal variations controlled by the solar ultraviolet flux
Cecconi, B.; Lamy, L.; Fujimoto, M. +9 more
Saturn's auroral activities have been suggested to be controlled by the seasonal variations of the polar ionospheric conductivities and atmospheric conditions associated with the solar extreme ultraviolet (EUV) flux. However, they have not yet been explained self-consistently by only the seasonal solar EUV effects. This study investigates the long…
Energy transfer across the magnetopause for northward and southward interplanetary magnetic fields
Jiang, Y.; Kabin, K.; Lu, J. Y. +2 more
A three-dimensional adaptive magnetohydrodynamic (MHD) model is used to examine the energy flow from the solar wind to the magnetosphere. Using the model, we directly compute fluxes of mechanical and electromagnetic energy across the magnetopause surface. For northward IMF, most of the energy flux inflow occurs near the polar cusps on magnetopause…
Transport of cold ions from the polar ionosphere to the plasma sheet
Fränz, M.; Wei, Y.; Daly, P. W. +8 more
Ionospheric outflow is believed to be a significant contribution to the magnetospheric plasma population. Ions are extracted from the ionosphere and transported downtail by the large-scale convection motion driven by dayside reconnection. In this paper, we use a comprehensive data set of cold ion (total energy less than 70 eV) measurements combine…
Signatures of magnetospheric injections in Saturn's aurora
Krupp, N.; Roussos, E.; Mitchell, D. G. +6 more
We report on the evolution of auroral structures based on two 3 h sequences of Saturn's northern hemisphere obtained with the UVIS instrument on board Cassini, and we discuss their possible association with injections in the magnetosphere of Saturn. Simultaneously with the UV auroral structures, we observe Energetic Neutral Atom (ENA) enhancements…
On the application of ensemble modeling techniques to improve ambient solar wind models
Riley, Pete; Linker, Jon A.; Mikić, Zoran
Ensemble modeling is a method of prediction based on the use of a representative sample of possible future states. Global models of the solar corona and inner heliosphere are now maturing to the point of becoming predictive tools; thus, it is both meaningful and necessary to quantitatively assess their uncertainty and limitations. In this study, w…
UVCS/SOHO catalog of coronal mass ejections from 1996 to 2005: Spectroscopic proprieties
Raymond, J. C.; Ciaravella, A.; Giordano, S. +2 more
Ultraviolet spectra of the extended solar corona have been routinely obtained by SOHO/UltraViolet Coronagraph Spectrometer (UVCS) since 1996. Sudden variations of spectral parameters are mainly due to the detection of coronal mass ejections (CMEs) crossing the instrumental slit. We present a catalog of CME ultraviolet spectra based upon a systemat…