Search Publications
Temporal Variations of High-Degree Solar p-Modes from GONG and MDI
Howe, Rachel; Hill, Frank; Jain, Kiran +4 more
We study temporal variations in the amplitudes and widths of high-degree acoustic modes in the quiet and active Sun by applying ring-diagram technique to the GONG+ and MDI Dopplergrams during the declining phase of cycle 23. The increase in amplitudes and decrease in line-widths in the declining phase of the solar activity is in agreement with pre…
On The Propagation And Modulation Of Electrostatic Solitary Waves Observed Near The Magnetopause On Cluster
Gurnett, D. A.; Lakhina, G. S.; Pickett, J. S. +15 more
We present the results of a study of Electrostatic Solitary Waves (ESWs) in which propagation of a series of noncyclical ESWs is observed from one Cluster spacecraft to another over distances as great as tens of km and time lags as great as a few tens of ms. This propagation study was conducted for locations near the magnetopause on the magnetoshe…
The coronal mass ejection associated with the loop eruption and coronal dimmings on 2009 December 13
Yang, L. H.; Zheng, Ruisheng; Jiang, Y. C. +1 more
By using the multi-wavelength observations from the Solar Terrestrial Relations Observatory (STEREO), the Solar and Heliospheric Observatory (SOHO), the Transition Region and Coronal Explorer (TRACE) and the HINODE, we study a coronal mass ejection (CME) and associated coronal dimming occurred on 2009 December 13, as a consequence of the expansion…
Filament destabilization and CME release during a long duration flare
Romano, P.; Contarino, L.; Zuccarello, F. +3 more
Context. During complex and long duration solar flares, several filament destabilizations or eruptions can occur that are often related to coronal mass ejections (CMEs).
Aims: We describe the study of an X3.8 long duration event (LDE) that occurred in NOAA 10720 on 17 January 2005 and was characterized by three filament destabilizations and t…
A Far-Ultraviolet Spectroscopic Analysis of BZ Ursae Majoris
Sion, Edward M.; Godon, Patrick; Gänsicke, Boris T. +1 more
We present an analysis of the Hubble Space Telescope/Space Telescope Imaging Spectrograph (HST/STIS) far-ultraviolet snapshot spectrum of the dwarf nova BZ UMa taken during quiescence. We find that the flux continuum is consistent with that of a white dwarf atmosphere with a temperature of 15,000 K, a projected rotational velocity of 200 km/s, non…
Angular-degree dependence of p-mode frequencies during solar cycle 23
Hill, F.; Salabert, D.; Garcia, R. A. +3 more
We analyze simultaneous helioseismic observations collected by the ground- and space-based instruments during solar cycle 23 by computing oscillation frequencies for low- and intermediate-degree p-modes on a time scale of 36 days. We find that the frequency shifts corresponding to different angular degree, ell, indicate different epochs for the on…
Distributions of Energy and Mass of Coronal Mass Ejections
Li, K. J.; Xu, J. C.; Gao, P. X.
The present study investigates the energy and mass distributions of all (11 322) coronal mass ejections (CMEs), 1406 CMEs associated solely with flares (FL CMEs), and 325 CMEs associated solely with filament eruptions (FE CMEs), all of which were observed by the Large Angle and Spectrometric Coronagraph on board the Solar and Heliospheric Observat…
Localized averaging kernels for probing the deep meridional flow with data from GONG, MDI and HMI
Roth, M.; Doerr, H. -P.
The Fourier-Legendre decomposition (FLD) method to study wave absorption in sunspots is a helioseismic technique which is also suited for the measurement of the meridional flow. Because the FLD method is sensible to low-degree oscillation modes, it bears the potential to be used to probe the average meridional flow in much deeper layers as it is c…
Laboratory and In-Flight Measurements at 10-55 K of InSb Near-Infrared Detector Performance for the Warm Mission of the AKARI Satellite
Oyabu, Shinki; Kaneda, Hidehiro; Ishihara, Daisuke +2 more
The warm mission phase of AKARI, the Japanese infrared astronomical satellite, has started after its 180 liter liquid helium cryogen was exhausted. Since then, we have conducted near-infrared observations with the Infrared Camera (IRC), while the telescope is slowly warming up. To explore the possibility of continuing observations at higher temper…
Electromagnetic ion-cyclotron instability driven by combined loss-cone and temperature anisotropy distribution of suprathermal ions
Hua, YuePing; Wu, DeJin; Wang, DeYu
Electromagnetic ion cyclotron (EMIC) waves, particularly their generation and excitation mechanisms, have been a subject of wide interest because of their potential importance in ion acceleration and heating. In this work, the parameter-dependence of EMIC instabilities is investigated with a combined loss-cone and temperature anisotropy distributi…