Cluster spacecraft observations of a ULF wave enhanced by Space Plasma Exploration by Active Radar (SPEAR)

Space Plasma Exploration by Active Radar (SPEAR) is a high-latitude ionospheric heating facility capable of exciting ULF waves on local magnetic field lines. We examine an interval from 1 February 2006 when SPEAR was transmitting a 1 Hz modulation signal with a 10 min on-off cycle. Ground magnetometer data indicated that SPEAR modulated currents in the local ionosphere at 1 Hz, and enhanced a natural field line resonance with a 10 min period. During this interval the Cluster spacecraft passed over the heater site. Signatures of the SPEAR-enhanced field line resonance were present in the magnetic field data measured by the magnetometer on-board Cluster-2. These are the first joint ground- and space-based detections of field line tagging by SPEAR

Vertical emissivity profiles of Jupiter's northern H-3(+) and H-2 infrared auroras observed by Subaru/IRCS

We resolved the vertical emissivity profiles of H-3(+) overtone, H-3(+) hot overtone, and H-2 emission lines of the Jovian northern auroras in K band obtained in December 2011 observed by the IR Camera and Spectrograph of the Subaru 8.2m telescope with the adaptive optics system (AO188). The spatial resolution achieved was similar to 0.2 arcsec, corresponding to similar to 600 km at Jupiter. We derived the vertical emissivity profiles at three polar regions close to the Jovian limb. The H-3(+) overtone and H-3(+) hot overtone lines had similar peak altitudes of 700-900 km and 680-950 km above the 1 bar level, which were 100-300 km and 150-420 km lower, respectively, than the model values. On the contrary, the H-2 peak emission altitude was high, 590-720 km above the 1 bar level. It was consistent with the value expected for precipitation of similar to 1 keV electron, which favors a higher-altitude emissivity profile. We concluded that the lower peak altitudes of H-3(+) overtone and hot overtone lines were caused by the nonlocal thermodynamic equilibrium effect stronger than the model assumption. We could reproduce the observational emissivity profiles from the model by including this effect. It has been proposed that neutral H-2 and ionized H-3(+) emissions can have different source altitudes because of their different morphologies and velocities; however, our observed results with a general circulation model show that the peak emission altitudes of H-3(+) and H-2 can be similar even with different velocities

Cassini observations of ion and electron beams at Saturn and their relationship to infrared auroral arcs

We present Cassini Visual and Infrared Mapping Spectrometer observations of infrared auroral emissions from the noon sector of Saturn's ionosphere revealing multiple intense auroral arcs separated by dark regions poleward of the main oval. The arcs are interpreted as the ionospheric signatures of bursts of reconnection occurring at the dayside magnetopause. The auroral arcs were associated with upward field-aligned currents, the magnetic signatures of which were detected by Cassini at high planetary latitudes. Magnetic field and particle observations in the adjacent downward current regions showed upward bursts of 100–360 keV light ions in addition to energetic (hundreds of keV) electrons, which may have been scattered from upward accelerated beams carrying the downward currents. Broadband, upward propagating whistler waves were detected simultaneously with the ion beams. The acceleration of the light ions from low altitudes is attributed to wave-particle interactions in the downward current regions. Energetic (600 keV) oxygen ions were also detected, suggesting the presence of ambient oxygen at altitudes within the acceleration region. These simultaneous in situ and remote observations reveal the highly energetic magnetospheric dynamics driving some of Saturn's unusual auroral features. This is the first in situ identification of transient reconnection events at regions magnetically conjugate to Saturn's magnetopause

Simultaneous Cassini VIMS and UVIS observations of Saturn's southern aurora: Comparing emissions from H, H-2 and H-3(+) at a high spatial resolution

Here, for the first time, temporally coincident and spatially overlapping Cassini VIMS and UVIS observations of Saturn's southern aurora are presented. Ultraviolet auroral H and H-2 emissions from UVIS are compared to infrared H-3(+) emission from VIMS. The auroral emission is structured into three arcs - H, H-2 and H-3(+) are morphologically identical in the bright main auroral oval (similar to 73 degrees S), but there is an equatorward arc that is seen predominantly in H (similar to 70 degrees S), and a poleward arc (similar to 74 degrees S) that is seen mainly in H-2 and H-3(+). These observations indicate that, for the main auroral oval, UV emission is a good proxy for the infrared H-3(+) morphology (and vice versa), but for emission either poleward or equatorward this is no longer true. Hence, simultaneous UV/IR observations are crucial for completing the picture of how the atmosphere interacts with the magnetosphere

The active region source of a type III radio storm observed by Parker Solar Probe during Encounter 2

Context. To investigate the source of a type III radio burst storm during encounter 2 of NASA's Parker Solar Probe (PSP) mission. Aims. It was observed that in encounter 2 of NASA's Parker Solar Probe mission there was a large amount of radio activity, and in particular a noise storm of frequent, small type III bursts from 31st March to 6th April 2019. Our aim is to investigate the source of these small and frequent bursts. Methods. In order to do this, we analysed data from the Hinode EUV Imaging Spectrometer (EIS), PSP FIELDS, and the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA). We studied the behaviour of active region 12737, whose emergence and evolution coincides with the timing of the radio noise storm and determined the possible origins of the electron beams within the active region. To do this, we probe the dynamics, Doppler velocity, non-thermal velocity, FIP bias, densities, and carry out magnetic modelling. Results. We demonstrate that although the active region on the disk produces no significant flares, its evolution indicates it is a source of the electron beams causing the radio storm. They most likely originate from the area at the edge of the active region that shows strong blue-shifted plasma. We demonstrate that as the active region grows and expands, the area of the blue-shifted region at the edge increases, which is also consistent with the increasing area where large-scale or expanding magnetic field lines from our modelling are anchored. This expansion is most significant between 1 and 4 April 2019, coinciding with the onset of the type III storm and the decrease of the individual burst's peak frequency, indicating the height at which the peak radiation is emitted increases as the active region evolves

Listening to the zoo: challenging zoo visiting conventions

This is the final version. Available on open access from Routledge via the DOI in this recordIn academic discourse, zoos have often been conceptualised as places of spectacle, with scholars focusing on the ways in which these institutions enable the viewing of other-thanhuman animals by human publics. This article, however, describes a set of guided listening visits conducted at two UK zoos. The visits were designed to question, disrupt and offer alternatives to ingrained zoo visiting conventions. They were also used to generate data on how sound mediates, or has the potential to mediate, relations between zoo visitors and zoo animals. The article describes the visits, reflects on their conceptual underpinnings and discusses themes emerging from participants’ experiences. It demonstrates the relevance of listening walks as a research methodology and illustrates the complexity of sound as a form of multispecies entanglement in the zoo context. The listening visits are also shown to indicate potential directions for wider changes in zoo visiting culture.Economic and Social Research Council (ESRC

Listening after the animals: sound and pastoral care in the zoo

This is the final version. Available on open access from Wiley via the DOI in this record.In anthropology and across the humanities and social sciences, zoos have tended to be theorized as places of spectacle. Scholars often focus on the ways in which these institutions enable the viewing of other-than-human animals by human publics. This article, however, uses sound-focused ethnographic fieldwork to engage with two UK zoos and to describe a particular mode of cross-species listening which is enacted by zookeepers. The concepts of pastoral care and control discussed by Foucault and applied to the zoo context by Braverman are productively reworked and reoriented in order to understand this form of listening. The article also demonstrates the interconnectedness of keeper, visitor and animal sound worlds, in the process generating an original perspective that complements and enriches conventional zoo studiesEconomic and Social Research Council (ESRC

Jupiter's X-ray and EUV auroras monitored by Chandra, XXM-Newton, and Hisaki satellite

Jupiter's X-ray auroral emission in the polar cap region results from particles which have undergone strong field-aligned acceleration into the ionosphere. The origin of precipitating ions and electrons and the time variability in the X-ray emission are essential to uncover the driving mechanism for the high-energy acceleration. The magnetospheric location of the source field line where the X-ray is generated is likely affected by the solar wind variability. However, these essential characteristics are still unknown because the long-term monitoring of the X-rays and contemporaneous solar wind variability has not been carried out. In April 2014, the first long-term multiwavelength monitoring of Jupiter's X-ray and EUV auroral emissions was made by the Chandra X-ray Observatory, XMM-Newton, and Hisaki satellite. We find that the X-ray count rates are positively correlated with the solar wind velocity and insignificantly with the dynamic pressure. Based on the magnetic field mapping model, a half of the X-ray auroral region was found to be open to the interplanetary space. The other half of the X-ray auroral source region is magnetically connected with the prenoon to postdusk sector in the outermost region of the magnetosphere, where the Kelvin-Helmholtz (KH) instability, magnetopause reconnection, and quasiperiodic particle injection potentially take place. We speculate that the high-energy auroral acceleration is associated with the KH instability and/or magnetopause reconnection. This association is expected to also occur in many other space plasma environments such as Saturn and other magnetized rotators

How Ubiquitin Unfolds after Transfer into the Gas Phase

The structural evolution of ubiquitin after transfer into the gas phase was studied by electron capture dissociation. Site-specific fragment yields show that ubiquitin’s solution fold is overall unstable in the gas phase, but unfolding caused by loss of solvent is slowest in regions stabilized by salt bridges

Saturn's equinoctial auroras

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95061/1/grl26673.pd