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Particle dynamics in a non-flaring solar active region model
Parnell, C. E.; Neukirch, T.; Threlfall, J. +1 more
Aims: The aim of this work is to investigate and characterise particle behaviour in an (observationally-driven) 3D magnetohydrodynamic (MHD) model of the solar atmosphere above a slowly evolving, non-flaring active region.
Methods: We use a relativistic guiding-centre particle code to investigate the behaviour of selected particle orbits…
Observations of high-plasma density region in the inner coma of 67P/Churyumov-Gerasimenko during early activity
Edberg, N. J. T.; Simon Wedlund, C.; Eriksson, A. I. +5 more
In 2014 September, as Rosetta transitioned to close bound orbits at 30 km from comet 67P/Churyumov-Gerasimenko, the Rosetta Plasma Consortium Langmuir probe (RPC-LAP) data showed large systematic fluctuations in both the spacecraft potential and the collected currents. We analyse the potential bias sweeps from RPC-LAP, from which we extract three …
Pulsations of the polar cusp aurora at Saturn
Krupp, N.; Roussos, E.; Mitchell, D. G. +4 more
The magnetospheric cusp is a region connecting the interplanetary environment to the ionosphere and enabling solar wind particles to reach the ionosphere. We report the detection of several isolated high-latitude auroral emissions with the Ultraviolet Imaging Spectrograph of the Cassini spacecraft. We suggest that these auroral spots, located in t…
Thermal properties of Rhea's poles: Evidence for a meter-deep unconsolidated subsurface layer
Spencer, J. R.; Howett, C. J. A.; Segura, M. +2 more
Cassini's Composite Infrared Spectrometer (CIRS) observed both of Rhea's polar regions during a close (2000 km) flyby on 9th March 2013 during orbit 183. Rhea's southern pole was again observed during a more distant (51,000 km) flyby on 10th February 2015 during orbit 212. The results show Rhea's southern winter pole is one of the coldest places d…
AGN-driven perturbations in the intracluster medium of the cool-core cluster ZwCl 2701
Naik, Sachindra; Vagshette, Nilkanth D.; Sonkamble, Satish S. +1 more
We present the results obtained from a total of 123 ks X-ray (Chandra) and 8 h of 1.4 GHz radio (Giant Metrewave Radio Telescope - GMRT) observations of the cool-core cluster ZwCl 2701 (z = 0.214). These observations of ZwCl 2701 showed the presence of an extensive pair of ellipsoidal cavities along the east and west directions within the central …
A Nanoflare-based Cellular Automaton Model and the Observed Properties of the Coronal Plasma
Klimchuk, James A.; López Fuentes, Marcelo
We use the cellular automaton model described in López Fuentes & Klimchuk to study the evolution of coronal loop plasmas. The model, based on the idea of a critical misalignment angle in tangled magnetic fields, produces nanoflares of varying frequency with respect to the plasma cooling time. We compare the results of the model with active reg…
Revised wavelength and spectral response calibrations for AKARI near-infrared grism spectroscopy: Cryogenic phase
Nakagawa, Takao; Baba, Shunsuke; Isobe, Naoki +6 more
We perform revised spectral calibrations for the AKARI near-infrared grism to correct quantitatively for the effect of the wavelength-dependent refractive index. The near-infrared grism covering the wavelength range of 2.5-5.0 µm, with a spectral resolving power of 120 at 3.6 µm, is found to be contaminated by second-order light at wav…
Attitude reconstruction of ROSETTA's Lander PHILAE using two-point magnetic field observations by ROMAP and RPC-MAG
Richter, Ingo; Auster, Hans-Ulrich; Heinisch, Philip +5 more
As part of the European Space Agency's ROSETTA Mission the Lander PHILAE touched down on comet 67P/Churyumov-Gerasimenko on November 12, 2014. The magnetic field has been measured onboard the orbiter and the lander. The orbiter's tri-axial fluxgate magnetometer RPC-MAG is one of five sensors of the ROSETTA Plasma Consortium. The lander is also equ…
Correlation of Coronal Plasma Properties and Solar Magnetic Field in a Decaying Active Region
Warren, Harry P.; Ugarte-Urra, Ignacio; Young, Peter R. +2 more
We present the analysis of a decaying active region observed by the EUV Imaging Spectrometer on Hinode during 2009 December 7-11. We investigated the temporal evolution of its structure exhibited by plasma at temperatures from 300,000 to 2.8 million degrees, and derived the electron density, differential emission measure, effective electron temper…
Eight-color maps of Titan's surface from spectroscopy with Huygens' DISR
Karkoschka, Erich; Schröder, Stefan E.
During the descent of the Huygens probe in Titan's atmosphere, the Descent Imager/Spectral Radiometer (DISR) acquired spectra of 3660 locations within 250 km of the landing site. Each spectrum consisted of 200 resolution elements between 480 and 960 nm wavelength. With the help of radiative transfer models, contributions from the atmosphere and su…