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Chromospheric Alfvénic Waves Strong Enough to Power the Solar Wind
Schrijver, C. J.; Ichimoto, K.; De Pontieu, B. +11 more
Alfvén waves have been invoked as a possible mechanism for the heating of the Sun's outer atmosphere, or corona, to millions of degrees and for the acceleration of the solar wind to hundreds of kilometers per second. However, Alfvén waves of sufficient strength have not been unambiguously observed in the solar atmosphere. We used images of high te…
The Process of Tholin Formation in Titan’s Upper Atmosphere
Coates, A. J.; Young, D. T.; Waite, J. H. +4 more
Titan’s lower atmosphere has long been known to harbor organic aerosols (tholins) presumed to have been formed from simple molecules, such as methane and nitrogen (CH4 and N2). Up to now, it has been assumed that tholins were formed at altitudes of several hundred kilometers by processes as yet unobserved. Using measurements …
Evidence for Alfvén Waves in Solar X-ray Jets
Weber, M.; Golub, L.; Kano, R. +11 more
Coronal magnetic fields are dynamic, and field lines may misalign, reassemble, and release energy by means of magnetic reconnection. Giant releases may generate solar flares and coronal mass ejections and, on a smaller scale, produce x-ray jets. Hinode observations of polar coronal holes reveal that x-ray jets have two distinct velocities: one nea…
Chromospheric Anemone Jets as Evidence of Ubiquitous Reconnection
Matsumoto, Takuma; Shibata, Kazunari; Nishizuka, Naoto +19 more
The heating of the solar chromosphere and corona is a long-standing puzzle in solar physics. Hinode observations show the ubiquitous presence of chromospheric anemone jets outside sunspots in active regions. They are typically 3 to 7 arc seconds = 2000 to 5000 kilometers long and 0.2 to 0.4 arc second = 150 to 300 kilometers wide, and their veloci…
Coronal Transverse Magnetohydrodynamic Waves in a Solar Prominence
Lites, B. W.; Ichimoto, K.; Shibata, K. +10 more
Solar prominences are cool 104 kelvin plasma clouds supported in the surrounding 106 kelvin coronal plasma by as-yet-undetermined mechanisms. Observations from Hinode show fine-scale threadlike structures oscillating in the plane of the sky with periods of several minutes. We suggest that these represent Alfvén waves propagat…
Subsurface Radar Sounding of the South Polar Layered Deposits of Mars
Gurnett, Donald A.; Stofan, Ellen R.; Frigeri, Alessandro +21 more
The ice-rich south polar layered deposits of Mars were probed with the Mars Advanced Radar for Subsurface and Ionospheric Sounding on the Mars Express orbiter. The radar signals penetrate deep into the deposits (more than 3.7 kilometers). For most of the area, a reflection is detected at a time delay that is consistent with an interface between th…
Tracking Solar Gravity Modes: The Dynamics of the Solar Core
García, Rafael A.; Turck-Chièze, Sylvaine; Mathur, Savita +5 more
Solar gravity modes have been actively sought because they directly probe the solar core (below 0.2 solar radius), but they have not been conclusively detected in the Sun because of their small surface amplitudes. Using data from the Global Oscillation at Low Frequency instrument, we detected a periodic structure in agreement with the period separ…
Martian Atmospheric Erosion Rates
Barabash, Stas; Lundin, Rickard; Fedorov, Andrei +1 more
Mars was once wet but is now dry, and the fate of its ancient carbon dioxide atmosphere is one of the biggest puzzles in martian planetology. We have measured the current loss rate due to the solar wind interaction for different species: Q(O+) = 1.6·1023 per second = 4 grams per second (g s-1), Q(O2…
Continuous Plasma Outflows from the Edge of a Solar Active Region as a Possible Source of Solar Wind
Golub, Leon; DeLuca, Edward E.; Harra, Louise K. +18 more
The Sun continuously expels a huge amount of ionized material into interplanetary space as the solar wind. Despite its influence on the heliospheric environment, the origin of the solar wind has yet to be well identified. In this paper, we report Hinode X-ray Telescope observations of a solar active region. At the edge of the active region, locate…
The Variable Rotation Period of the Inner Region of Saturn’s Plasma Disk
Gurnett, D. A.; Persoon, A. M.; Dougherty, M. K. +4 more
We show that the plasma and magnetic fields in the inner region of Saturn’s plasma disk rotate in synchronism with the time-variable modulation period of Saturn’s kilometric radio emission. This relation suggests that the radio modulation has its origins in the inner region of the plasma disk, most likely from a centrifugally driven convective ins…