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Comparative aeronomy: Molecular ionospheres at Earth and Mars
Withers, Paul; Moore, Luke; Vogt, Marissa F. +6 more
The ionospheres in our solar system vary not only in their electron densities but also in the dominance of atomic versus molecular ions at their altitudes of peak plasma density. With the exception of Earth's F layer composed of atomic oxygen ions and electrons, all other planets have their peak ionospheric layers composed of molecular ions and el…
Fine-pitch CdTe detector for hard X-ray imaging and spectroscopy of the Sun with the FOXSI rocket experiment
Takahashi, Tadayuki; Saito, Shinya; Watanabe, Shin +8 more
We have developed a fine-pitch hard X-ray (HXR) detector using a cadmium telluride (CdTe) semiconductor for imaging and spectroscopy for the second launch of the Focusing Optics Solar X-ray Imager (FOXSI). FOXSI is a rocket experiment to perform high sensitivity HXR observations from 4 to 15 keV using the new technique of HXR focusing optics. The …
Emission of hydrogen energetic neutral atoms from the Martian subsolar magnetosheath
Kallio, E.; Barabash, S.; Futaana, Y. +3 more
We have simulated the hydrogen energetic neutral atom (ENA) emissions from the subsolar magnetosheath of Mars using a hybrid model of the proton plasma charge exchanging with the Martian exosphere to study statistical features revealed from the observations of the Neutral Particle Detectors on Mars Express. The simulations reproduce well the obser…
Solar cycle variations in ion composition in the dayside ionosphere of Titan
Wahlund, J. -E.; Edberg, N. J. T.; Waite, J. H. +4 more
One Titanian year spans over two complete solar cycles, and the solar irradiance has a significant effect on ionospheric densities. Solar cycle 24 has been one of the quietest cycles on record. In this paper we show data from the Cassini ion and neutral mass spectrometer (INMS) and the radio and plasma wave science Langmuir probe spanning the time…
Cluster observations of non-time continuous magnetosonic waves
Boardsen, Scott A.; Sibeck, David G.; Walker, Simon N. +3 more
Equatorial magnetosonic waves are normally observed as temporally continuous sets of emissions lasting from minutes to hours. Recent observations, however, have shown that this is not always the case. Using Cluster data, this study identifies two distinct forms of these non-temporally continuous emissions. The first, referred to as rising tone emi…
Partitioning of integrated energy fluxes in four tail reconnection events observed by Cluster
Goldstein, Melvyn; Gurgiolo, Chris; Thaller, Scott +4 more
We present the partitioning of integrated energy flux from four tail reconnection events observed by Cluster, focusing on the relative contributions of Poynting flux, electron, H+ and O+ enthalpy, and kinetic energy flux in the tailward and earthward directions in order to study temporal and spatial features of each event. We further subdivide the…
On improving the accuracy of electron density profiles obtained at high altitudes by the ionospheric sounder on the Mars Express spacecraft
Gurnett, D. A.; Němec, F.; Morgan, D. D.
We attempt to improve the standard inversion routine used to obtain electron density profiles from the data measured by the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) topside radar sounder on board the Mars Express spacecraft. Artificial ionospheric traces corresponding to how the MARSIS instrument would see model electro…
Hemispheric asymmetry in the near-Venusian magnetotail during solar maximum
Zhang, T. L.; Baumjohann, W.; Xiao, S. D.
During solar minimum the near-Venusian magnetotail exhibits a hemispheric asymmetry in the cross-tail field distribution. It implies that the magnetic field lines in the -E hemisphere are wrapped more tightly around Venus than in the +E hemisphere. Therefore, a strong field reversal region occurs in the magnetotail, which is prone to the magnetic …
Coronal magnetic field profiles from shock-CME standoff distances
Gopalswamy, N.; Cairns, Iver H.; Yashiro, S. +1 more
Coronagraphs observe coronal mass ejections (CMEs) and driven shocks in white light images. From these observations the shock's speed and the shock's standoff distance from the CME's leading edge can be derived. Using these quantities, theoretical relationships between the shock's Alfvénic Mach number MA and standoff distance, and empirical radial…
A 17 June 2011 polar jet and its presence in the background solar wind
Jackson, B. V.; Buffington, A.; Hick, P. P. +3 more
High-speed jet responses in the polar solar wind are enigmatic. Here we measure a jet response that emanates from the southern polar coronal hole on 17 June 2011 at the extreme speed of over 1200 km/s. This response was recorded from the Sun-Earth line in Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA) and Large Angle and Spectro…