Search Publications
Knickpoints in Martian channels indicate past ocean levels
Duran, Sergio; Coulthard, Tom J.; Baynes, Edwin R. C.
On Mars, the presence of extensive networks of sinuous valleys and large channels provides evidence for a wetter and warmer environment where liquid water was more abundant than it is at present. We undertook an analysis of all major channel systems on Mars and detected sharp changes in elevation along the river long profiles associated with steep…
Observing Kelvin-Helmholtz instability in solar blowout jet
Hou, Yijun; Yang, Shuhong; Zhang, Jun +2 more
Kelvin-Helmholtz instability (KHI) is a basic physical process in fluids and magnetized plasmas, with applications successfully modelling e.g. exponentially growing instabilities observed at magnetospheric and heliospheric boundaries, in the solar or Earth's atmosphere and within astrophysical jets. Here, we report the discovery of the KHI in sola…
Development of an ensemble Kalman filter data assimilation system for the Venusian atmosphere
Sugimoto, Norihiko; Takagi, Masahiro; Kouyama, Toru +3 more
The size and mass of Venus is similar to those of the Earth; however, its atmospheric dynamics are considerably different and they are poorly understood due to limited observations and computational difficulties. Here, we developed a data assimilation system based on the local ensemble transform Kalman filter (LETKF) for a Venusian Atmospheric GCM…
Unprecedented Fine Structure of a Solar Flare Revealed by the 1.6 m New Solar Telescope
Xu, Yan; Cao, Wenda; Liu, Chang +3 more
Solar flares signify the sudden release of magnetic energy and are sources of so called space weather. The fine structures (below 500 km) of flares are rarely observed and are accessible to only a few instruments world-wide. Here we present observation of a solar flare using exceptionally high resolution images from the 1.6 m New Solar Telescope (…
Weak, Quiet Magnetic Fields Seen in the Venus Atmosphere
Luhmann, J. G.; Russell, C. T.; Zhang, T. L. +2 more
The existence of a strong internal magnetic field allows probing of the interior through both long term changes of and short period fluctuations in that magnetic field. Venus, while Earth’s twin in many ways, lacks such a strong intrinsic magnetic field, but perhaps short period fluctuations can still be used to probe the electrical conductivity o…
Distinct characteristics of asymmetric magnetic reconnections: Observational results from the exhaust region at the dayside magnetopause
Zhang, Y. C.
Magnetic reconnection plays a key role in the conversion of magnetic energy into the thermal and kinetic energy of plasma. On either side of the diffusion region in space plasma, the conditions for the occurrence of reconnections are usually not symmetric. Previous theoretical studies have predicted that reconnections under asymmetric conditions w…
Solution structure of the isolated histone H2A-H2B heterodimer
Moriwaki, Yoshihito; Yamane, Tsutomu; Ohtomo, Hideaki +6 more
During chromatin-regulated processes, the histone H2A-H2B heterodimer functions dynamically in and out of the nucleosome. Although detailed crystal structures of nucleosomes have been established, that of the isolated full-length H2A-H2B heterodimer has remained elusive. Here, we have determined the solution structure of human H2A-H2B by NMR coupl…
A likely inverse-Compton emission from the Type IIb SN 2013df
Kong, A. K. H.; Li, K. L.
The inverse-Compton X-ray emission model for supernovae has been well established to explain the X-ray properties of many supernovae for over 30 years. However, no observational case has yet been found to connect the X-rays with the optical lights as they should be. Here, we report the discovery of a hard X-ray source that is associated with a Typ…
Strong Temporal Variation Over One Saturnian Year: From Voyager to Cassini
West, Robert A.; Baines, Kevin H.; Nixon, Conor A. +14 more
Here we report the combined spacecraft observations of Saturn acquired over one Saturnian year (~29.5 Earth years), from the Voyager encounters (1980-81) to the new Cassini reconnaissance (2009-10). The combined observations reveal a strong temporal increase of tropic temperature (~10 Kelvins) around the tropopause of Saturn (i.e., 50 mbar), which…