Hercules A

Hercules A
Radio-Optical View of the Galaxy Hercules A - Many thanks to: NASA, ESA, S. Baum and C. O'Dea (RIT), R. Perley and W. Cotton (NRAO/AUI/NSF), and the Hubble Heritage Team (STScI/AURA)

Monday, December 11, 2017

Links to abstracts for 9 Juno related papers at AGU 2017 Fall Meeting

Links to abstracts for 9 Juno related papers at AGU 2017 Fall Meeting

U21A-01: A comparative examination of auroral acceleration processes at Jupiter and Earth as enabled by the Juno mission to Jupiter


"Particle distributions observed by Juno’s Energetic Particle Detector Investigation (JEDI) at low altitudes over Jupiter’s polar regions are exceedingly diverse in directionality and in the shapes of their 3-dimensional energy distributions. Asymmetric, bi-directional angular beams with broad energy distributions are often observed near Jupiter’s main auroral oval with considerable variability as to whether upward or downward intensities are the strongest. Signatures of upward and downward magnetic field-aligned potentials, with inferred potentials up to 100’s of kV are sometimes observed, but unlike at Earth, these potentials do not seem to be associated with the strongest discrete-like auroral emission intensities. Particle distributions have similarities to those observed at Earth over the various phenomenological auroral emission regions, but they are observed in unexpected places with respect to the strongest auroral emission regions, and the jovian distributions are much more energetic. We present a comparative examination of auroral acceleration processes observed at Earth and Jupiter in relation to the respective auroral emission regions."

https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/239529

U21A-02: An overview of the first year of observations of Jupiter’s auroras by Juno-UVS with multi-wavelength comparisons


"Juno’s Ultraviolet Spectrograph (Juno-UVS) has observed the Jovian aurora during eight perijove passes. UVS typically observes Jupiter for 10 hours centered on closest approach in a series of swaths, with one swath per Juno spin (~30s). During this period the spacecraft range to Jupiter’s aurora decreases from ~6 RJ to ~0.3 RJ (or less) in the north, and then reverses this in the south, so that spatial resolution changes dramatically. A scan mirror is used to target different features or raster across the entire auroral region. Juno-UVS observes a particular location for roughly 17 ms/swath, so the series of swaths provide snapshots of ultraviolet auroral brightness and color. A variety of forms and activity levels are represented in the Juno-UVS data–some have been described before with HST observations, but others are new. One interesting result is that the color ratio, often used as a proxy for energetic particle precipitation, may instead (in certain regions) indicate excitation of H2 by low-energy ionospheric electrons. Additional results from comparisons with simultaneous observations at x-ray, visible, and near-IR wavelengths will also be presented."

https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/234660

U21A-03: The Jupiter gravity field from the first year of Juno science operations


"Through November 2017 the Juno spacecraft has completed nine science orbits about Jupiter. Five of the nine perijove passes, when the spacecraft was closest to Jupiter, were arranged to provide accurate measurements of the Doppler shift of the Juno radio signal in order to determine the Jupiter gravity field. The estimated gravity field has been used to place constraints on the interior structure of Jupiter and and effects caused by differential rotation. The Doppler measurements are also used to estimate the response of Jupiter to tides raised by the Galilean satellites, and the Jupiter rotation axis direction and precession rate. We report on the current status of the gravity estimates and the expected results from the rest of the mission duration."

https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/243436

U21A-04: Jupiter’s Magnetic Field and Magnetosphere after Juno’s First 8 Orbits 


"The Juno spacecraft entered polar orbit about Jupiter on July 4, 2016, embarking upon an ambitious mission to map Jupiter’s magnetic and gravitational potential fields and probe its deep atmosphere, in search of clues to the planet’s formation and evolution. Juno is also instrumented to conduct the first exploration of the polar magnetosphere and to acquire images and spectra of its polar auroras and atmosphere. Juno’s 53.5-day orbit trajectory carries her science instruments from pole to pole in approximately 2 hours, with a closest approach to within ~1.05 Rj of the center of the planet (one Rj = 71,492 km, Jupiter’s equatorial radius), just a few thousand km above the clouds. Repeated periapsis passes will eventually encircle the planet with a dense net of observations equally spaced in longitude (<12° at the equator) and optimized for characterization of the Jovian dynamo. Such close passages are sensitive to small spatial scale variations in the magnetic field and therefore many such passes are required to bring the magnetic field into focus. Nevertheless, after only 8 orbits, low-degree spherical harmonics can be extracted from a partial solution to a much more complicated representation (e.g., 20 degree/order), providing the first new information about Jupiter’s magnetic field in decades. Juno is equipped with two magnetometer sensor suites, located 10 and 12 m from the center of the spacecraft at the end of one of Juno’s three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads, providing accurate attitude determination for the FGM sensors. We present an overview of the magnetometer observations obtained during Juno’s first year in orbit in context with prior observations and those acquired by Juno’s other science instruments."

https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/244811

U21A-05: Results on Jupiter’s Atmosphere from the Juno Microwave Radiometer


"The Juno Microwave Radiometer (MWR) was designed to investigate Jupiter’s atmosphere and radiation belts as one of a suite of instruments on the Juno mission. The MWR’s main objective is to investigate the composition and dynamics of Jupiter’s neutral atmosphere. Juno has now completed eight perijove passes that sample the atmosphere approximately every 45° in longitude, and the MWR has completed its main collection of data pertaining to the composition and structure of Jupiter’s atmosphere. The primary results for atmospheric structure elaborate on the original discovery that the concentration of ammonia is far from uniformly mixed beneath its saturation level in the atmosphere and that deep atmospheric circulations control its distribution. Conversely, features of the deep circulation may be inferred from this distribution. Distinct circulation patterns are seen for three latitudinal regions: 1) Equatorial, where a column of increased ammonia concentration associated with the equatorial zone is sandwiched by off-equatorial regions of depleted ammonia in the north and south equatorial belts, with structure apparent to approximately the 100-bar pressure level, 2) Midlatitudes, where a stratified ammonia concentration appears stable, and 3) Polar, dominated by deep vertical structures associated with the observed surface vortices. Longitudinal structure is seen in the equatorial region primarily above the level of the water cloud around the 8-bar level, while significant structure appears small or absent outside and below this region. The ability of the MWR to detect lightning at its longest wavelengths was unexpected but sheds light on the presence of water and the distribution of strong convective regions in the atmosphere. The implications of these results for atmospheric dynamics and composition will be discussed."

https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/260075

U21A-06: One-Year Observations of Jupiter by the Jovian Infrared Auroral Mapper on Juno


"The Jovian InfraRed Auroral Mapper (JIRAM) [1] on board the Juno [2,3] spacecraft, is equipped with an infrared camera and a spectrometer working in the spectral range 2-5 μm. JIRAM was built to study the infrared aurora of Jupiter as well as to map the planet’s atmosphere in the 5 µm spectral region. The spectroscopic observations are used for studying clouds and measuring the abundance of some chemical species that have importance in the atmosphere’s chemistry, microphysics and dynamics like water, ammonia and phosphine.
During 2017 the instrument will operate during all 7 of Juno’s Jupiter flybys. JIRAM has performed several observations of the polar regions of the planet addressing the aurora and the atmosphere. Unprecedented views of the aurora and the polar atmospheric structures have been obtained. We present a survey of the most significant observations that the instrument has performed during the current year.
[1] Adriani A. et al., JIRAM, the Jovian Infrared Auroral Mapper. Space Sci. Rew., DOI: 10.1007/s11214-014-0094-y, 2014.
[2] Bolton S.J. et al., Jupiter’s interior and deep atmosphere: The initial pole-to-pole passes with the Juno spacecraft. Science DOI: 10.1126/science.aal2108, 2017.
[3] Connerney J. E.P. et al., Jupiter’s magnetosphere and aurorae observed by the Juno spacecraft during its first polar orbits. Science, DOI: 10.1126/science.aam5928, 2017."

https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/268990

U21A-07: Observations by the Juno Waves Investigation at Jupiter


"The Juno spacecraft successfully entered into a highly elliptic polar orbit of Jupiter in July 2016, providing a unique opportunity to explore the Jovian polar magnetosphere and the region between the rings and atmosphere. Juno’s science payload employs a suite of particle, field, and remote sensing instruments to characterize the Jovian magnetosphere and provide remote observations of Jupiter’s auroras. The radio and plasma wave instrument (“Waves”) measures one electric field component of waves in the frequency range of 50 Hz to 40 MHz and one magnetic field component of waves in the range of 50 Hz to 20 kHz. The initial orbits have revealed a number of radio and plasma wave phenomena related to auroral processes, including auroral hiss, electron phase space holes, and a number of encounters or near encounters with the auroral radio emission source regions. The Waves instrument also observes both electron and proton whistlers from lightning, and detects impulses due to impacts of micron-sized grains near Jupiter’s equator. In the outer magnetosphere, trapped continuum radiation is observed, and numerous magnetopause and bow shock crossings have been encountered. In this talk we provide an overview of these and other early results from the Juno Waves investigation."
https://doi.org/10.1002/2017GL072889,   https://doi.org/10.1002/2017GL072850,   https://doi.org/10.1002/2017GL073073

https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/247784

U21A-08: The first year of observations of Jupiter’s magnetosphere from Juno's Jovian Auroral Distributions Experiment (JADE)


"Juno observations of the Jovian plasma environment are made by the Jovian Auroral Distributions Experiment (JADE) which consists of two nearly identical electron sensors – JADE-E – and an ion sensor – JADE-I. JADE-E measures the electron distribution in the range of 100 eV to 100 keV and uses electrostatic deflection to measure the full pitch angle distribution. JADE-I measures the composition separated energy per charge in the range of 10 eV / q to 46 keV / q. The large orbit – apojove ~ 110 Rj, perijove ~1.05 Rj – allows JADE to periodically cross through the magnetopause into the magnetosheath, transverse the outer, middle, and inner magnetosphere, and measures the plasma population down to the ionosphere. We present here in situ plasma observations of the Jovian magnetosphere and topside ionosphere made by the JADE instrument during the first year in orbit.
Dawn-side crossings of the plasmapause have shown a general dearth of heavy ions except during some intervals at lower magnetic latitudes. Plasma disk crossings in the middle and inner magnetosphere show a mixture of heavy and light ions. During perijove crossings at high latitudes when Juno was connected to the Io torus, JADE-I observed heavy ions with energies consistent with a corotating pickup population. In the auroral regions the core of the electron energy distribution is generally from about 100 eV when on field lines that are connected to the inner plasmasheet, several keVs when connected to the outer plasmasheet, and tens of keVs when Juno is over the polar regions. JADE has observed upward electron beams and upward loss cones, both in the north and south auroral regions, and downward electron beams in the south. Some of the beams are of short duration (~ 1 s) implying that the magnetosphere has a very fine spatial and/or temporal structure within the auroral regions. Joint observations with the Waves instrument have demonstrated that the observed loss cone distributions provide sufficient growth rates to drive the cyclotron maser instability. The high velocity of the Juno spacecraft near perijove (~50 km/s) allows observations for of very low energy ions in the spacecraft ram direction, down to below 1 eV/q for protons."

https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/256709

U21A-09: JunoCam Images of Jupiter: Science from an Outreach Experiment


The Juno mission to Jupiter carries a visible imager on its payload primarily for outreach, and also very useful for jovian atmospheric science. Lacking a formal imaging science team, members of the public have volunteered to process JunoCam images. Lightly processed and raw JunoCam data are posted on the JunoCam webpage at https://missionjuno.swri.edu/junocam/processing. Citizen scientists download these images and upload their processed contributions.
JunoCam images through broadband red, green and blue filters and a narrowband methane filter centered at 889 nm mounted directly on the detector. JunoCam is a push-frame imager with a 58 deg wide field of view covering a 1600 pixel width, and builds the second dimension of the image as the spacecraft rotates. This design enables capture of the entire pole of Jupiter in a single image at low emission angle when Juno is ~1 hour from perijove (closest approach). At perijove the wide field of view images are high-resolution while still capturing entire storms, e.g. the Great Red Spot.
Juno’s unique polar orbit yields polar perspectives unavailable to earth-based observers or most previous spacecraft. The first discovery was that the familiar belt-zone structure gives way to more chaotic storms, with cyclones grouped around both the north and south poles [1, 2]. Recent time-lapse sequences have enabled measurement of the rotation rates and wind speeds of these circumpolar cyclones [3].
Other topics are being investigated with substantial, in many cases essential, contributions from citizen scientists. These include correlating the high resolution JunoCam images to storms and disruptions of the belts and zones tracked throughout the historical record. A phase function for Jupiter is being developed empirically to allow image brightness to be flattened from the subsolar point to the terminator. We are studying high hazes and the stratigraphy of the upper atmosphere, utilizing the methane filter, structures illuminated beyond the terminator, and clouds casting shadows. Numerous high altitude clouds have been detected and we are investigating whether they are the jovian equivalent of squall lines."

[1] Bolton, S. et al. (2017) Science 356:821; [2] Orton, G. et al. (2017) GRL 44:4599; [3] Adriani, A. et al. (2017) submitted to Nature.

https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/276208


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Introductory Radio Astronomy links:
http://herrero-radio-astronomy.blogspot.com/2015/06/introductory-radio-astronomy-references.html
Magnetosphere of Jupiter :
https://en.wikipedia.org/wiki/Magnetosphere_of_Jupiter
Jupiter events at Juno Waves and other observatories :
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-1-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-2-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-3-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-4-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/10/jupiter-events-5-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/10/jupiter-events-6-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/11/jupiter-events-7-at-juno-waves-and.html
Jupiter events at the University of Iowa Space Physics LWA1 Data Project :
http://herrero-radio-astronomy.blogspot.com/2017/08/jupiter-events-1-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/08/jupiter-events-2-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-3-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-4-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-5-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-6-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-7-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/11/jupiter-events-8-at-university-of-iowa.html
Examples of Jupiter events observed by Juno Waves :
http://herrero-radio-astronomy.blogspot.com/2017/05/examples-of-jupiter-events-observed-by.html
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Wednesday, November 15, 2017

Sun Earth Jupiter 20171021

...
Many thanks to: Taxpayers of the United States of America, the Juno, STEREO, WIND Spacecraft Teams, the Panetary Data System Team,  Prof. Dr. Kazumasa Imai Kochi National College of Technology Kochi Japan, Trinity College Dublin Ireland Astrophysics Group, United States NOAA SWPC, NASA Solar Dynamics Observatory Teams, Lockheed Martin Solar Laboratory, SOTERIA Project

With many thanks, Victor Herrero-Arrieta acknowledges the Nançay Radio Observatory / Unité Scientifique de Nançay of the Observatoire de Paris (USR 704-CNRS, supported by Université d’Orléans, OSUC, and Région Centre in France) for providing access to NDA observations accessible online at http://www.obs-nancay.fr 

Many thanks to: Taxpayers of France, French Air Force, Nancay Decametric Array Team at the Nancay Radio Astronomy Station of Paris Observatory. 

More on this subject:
http://herrero-radio-astronomy.blogspot.com/2017/10/sun-earth-jupiter-20171021.html
http://herrero-radio-astronomy.blogspot.com/2017/09/sun-earth-jupiter-20170926.html
http://herrero-radio-astronomy.blogspot.com/2017/08/sun-earth-jupiter-20170831.html
http://herrero-radio-astronomy.blogspot.com/2015/08/links-to-monthly-sun-earth-jupiter-posts.html?m=1

...
 Sun 171021 , M1 flare , CME , Jupiter approaching conjunction :






..

Jupiter Sun conjunction and Comet Machholz , 171026 at SOHO coronagraphs C2 C3 :













...

Saturday, November 4, 2017

Jupiter events 7 at Juno Waves and other observatories

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With many thanks from Victor Herrero-Arrieta to the Teams at Juno Waves, NASA Planetary Data System, STEREO A,  WIND, and the Tax Payers of the United States of America.
With many thanks, Victor Herrero-Arrieta acknowledges the Nançay Radio Observatory / Unité Scientifique de Nançay of the Observatoire de Paris (USR 704-CNRS, supported by Université d’Orléans, OSUC, and Région Centre in France) for providing access to NDA observations accessible online at http://www.obs-nancay.fr

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Introductory Radio Astronomy links:
http://herrero-radio-astronomy.blogspot.com/2015/06/introductory-radio-astronomy-references.html
Magnetosphere of Jupiter :
https://en.wikipedia.org/wiki/Magnetosphere_of_Jupiter
Jupiter events at Juno Waves and other observatories :
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-1-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-2-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-3-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-4-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/10/jupiter-events-5-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/10/jupiter-events-6-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/11/jupiter-events-7-at-juno-waves-and.html
Jupiter events at the University of Iowa Space Physics LWA1 Data Project :
http://herrero-radio-astronomy.blogspot.com/2017/08/jupiter-events-1-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/08/jupiter-events-2-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-3-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-4-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-5-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-6-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-7-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/11/jupiter-events-8-at-university-of-iowa.html
Examples of Jupiter events observed by Juno Waves :
http://herrero-radio-astronomy.blogspot.com/2017/05/examples-of-jupiter-events-observed-by.html
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Monday, October 23, 2017

A first study of Jupiter 160827 at NASA PDS and Kurth et al. 2017 "A new view..."

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With many thanks from Victor Herrero-Arrieta to the Teams at Juno Waves, NASA Planetary Data System, STEREO A,  WIND, and the Tax Payers of the United States of America.

With many thanks, Victor Herrero-Arrieta acknowledges the Nançay Radio Observatory / Unité Scientifique de Nançay of the Observatoire de Paris (USR 704-CNRS, supported by Université d’Orléans, OSUC, and Région Centre in France) for providing access to NDA observations accessible online at http://www.obs-nancay.fr
------
Magnetosphere of Jupiter :
https://en.wikipedia.org/wiki/Magnetosphere_of_Jupiter
Jupiter events at Juno Waves and other observatories :
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-1-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-2-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-3-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-4-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/10/jupiter-events-5-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/10/jupiter-events-6-at-juno-waves-and.html
Jupiter events at the University of Iowa Space Physics LWA1 Data Project :
http://herrero-radio-astronomy.blogspot.com/2017/08/jupiter-events-1-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/08/jupiter-events-2-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-3-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-4-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-5-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-6-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-7-at-university-of-iowa.html
Examples of Jupiter events observed by Juno Waves :
http://herrero-radio-astronomy.blogspot.com/2017/05/examples-of-jupiter-events-observed-by.html
-----

I refer to Kurth et al. 2017 "A new view of Jupiter’s auroral radio spectrum"

"...3. Discussion and Summary

187 The Juno Waves observations from perijove 1 reveal an overall structure for non-Io
188 related Jovian auroral radio emissions that consists primarily of V-shaped emissions in
189 frequency-time spectrograms in which the vertex falls close to the local electron cyclotron
190 frequency where the emissions are generally more intense. The intensification and the proximity
191 of the emission to fce provide the suggestion that at these times the spacecraft is close to a source
192 region. For some of the events, closer inspection shows the emission is at or even below fce and
193 the electron distribution function sometimes shows down-going beams and up-going loss cones.
194 Louarn et al. [2017] show that loss cone distributions observed in the vicinity of Event C are
195 sufficient to drive the cyclotron maser instability. Mauk et al. [2017] report loss cone features in
196 the more energetic electron observations made by the JEDI instrument at similar times as those
197 of interest, here. Hence, it will be important to consider the full range of electron distributions
198 before a final assessment of the distribution responsible for the radio emissions. We note,
199 however, that for the possible sources noted in the present work, the fact that the radio emissions
200 are not far below fce, hence, the resonant electrons cannot be much above the JADE electron
201 energy range.
202 The V-shaped emissions observed are almost certainly the result of the relative motion of
203 Juno with respect to CMI sources having thin conical sheet beaming patterns with large opening
204 angles [Kaiser and MacDowall, 1998; Queinnec and Zarka, 1998]. There are V-shaped
205 emissions both near AKR sources at Earth and Saturn, although these are typically filled as
206 opposed to the narrow features in Figure 2. Louis et al. [this issue] shows that some decametric
207 emissions near Perijove 1 have V-shaped emissions that are well modeled by simulations. This
208 suggests the V-shape may be related to sources that are restricted to one or a small set of field
209 lines. Future work will include modeling the frequency-time structure with tools such as those
210 described by Louis et al. [this issue] and Imai et al. [2017 a, b].
211 While there are few specific spectral features that provide accurate plasma frequencies, it
212 appears that fpe is of order 20 kHz throughout the Jovian polar region, hence, fce >> fpe for at least
213 events B and C. The situation is similar to that at Saturn where the density is so low that there is
214 no need for plasma cavities such as occur over Earth’s auroral regions to meet the fce >> fpe
215 requirement for the cyclotron maser instability.
216 Hess et al. [2008] examine various mechanisms by which electron acceleration events
217 observed by the Galileo plasma instrument near Io might generate CMI emissions. Provided the
218 plasma density in the source region is sufficiently low that Earth-like plasma cavities are not
219 required, they favor an oblique instability driven by heating which generates emissions with
220 beaming angles that vary along the Io flux tube with smaller angles at larger magnetic field
221 strengths (lower altitudes, higher frequencies). While the emissions reported herein are not Io
222 related, it is likely similar conical beaming occurs.
223 The first examination of radio emissions from low altitude, high latitude with Juno
224 provided an illuminating view of V-shaped frequency-time structures with vertices near fce and
225 sometimes covering virtually the full spectral range from kilometric to decametric frequencies.
226 Juno came at least close to up to five radio sources over about 18 hours near closest approach.
227 For some of the near-source crossings, electron observations at energies of a few to 10’s of keV
228 show loss cone and beam features that are reminiscent of terrestrial auroral kilometric sources.
229 Louarn et al. [2017] provide evidence that the distribution for Event C is sufficient to drive the
230 cyclotron maser instability, consistent with the observed emissions. It remains to model the
231 observed sources, as done by Louis et al. [this issue] for Io related emissions, to show that they
232 can result in the V-shaped frequency-time structures and to further investigate the energetic
233 electron distributions for their ability to drive the radio emissions. These observations, however,
234 serve to confirm that the CMI process is a universal process for the generation of auroral radio
235 emissions..."



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Thursday, October 12, 2017

Jupiter events 6 at Juno Waves and other observatories

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With many thanks from Victor Herrero-Arrieta to the Teams at Juno Waves, NASA Planetary Data System, STEREO A,  WIND, and the Tax Payers of the United States of America.

With many thanks, Victor Herrero-Arrieta acknowledges the Nançay Radio Observatory / Unité Scientifique de Nançay of the Observatoire de Paris (USR 704-CNRS, supported by Université d’Orléans, OSUC, and Région Centre in France) for providing access to NDA observations accessible online at http://www.obs-nancay.fr
------
Magnetosphere of Jupiter :
https://en.wikipedia.org/wiki/Magnetosphere_of_Jupiter
Jupiter events at Juno Waves and other observatories :
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-1-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-2-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-3-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-4-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/10/jupiter-events-5-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/10/jupiter-events-6-at-juno-waves-and.html
Jupiter events at the University of Iowa Space Physics LWA1 Data Project :
http://herrero-radio-astronomy.blogspot.com/2017/08/jupiter-events-1-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/08/jupiter-events-2-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-3-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-4-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-5-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-6-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-7-at-university-of-iowa.html
Examples of Jupiter events observed by Juno Waves :
http://herrero-radio-astronomy.blogspot.com/2017/05/examples-of-jupiter-events-observed-by.html
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About the usual names and fluxes for the planetary radio emission bands :





I refer to Kurth et al. 2017 "A new view of Jupiter’s auroral radio spectrum"

"...3. Discussion and Summary

187 The Juno Waves observations from perijove 1 reveal an overall structure for non-Io
188 related Jovian auroral radio emissions that consists primarily of V-shaped emissions in
189 frequency-time spectrograms in which the vertex falls close to the local electron cyclotron
190 frequency where the emissions are generally more intense. The intensification and the proximity
191 of the emission to fce provide the suggestion that at these times the spacecraft is close to a source
192 region. For some of the events, closer inspection shows the emission is at or even below fce and
193 the electron distribution function sometimes shows down-going beams and up-going loss cones.
194 Louarn et al. [2017] show that loss cone distributions observed in the vicinity of Event C are
195 sufficient to drive the cyclotron maser instability. Mauk et al. [2017] report loss cone features in
196 the more energetic electron observations made by the JEDI instrument at similar times as those
197 of interest, here. Hence, it will be important to consider the full range of electron distributions
198 before a final assessment of the distribution responsible for the radio emissions. We note,
199 however, that for the possible sources noted in the present work, the fact that the radio emissions
200 are not far below fce, hence, the resonant electrons cannot be much above the JADE electron
201 energy range.
202 The V-shaped emissions observed are almost certainly the result of the relative motion of
203 Juno with respect to CMI sources having thin conical sheet beaming patterns with large opening
204 angles [Kaiser and MacDowall, 1998; Queinnec and Zarka, 1998]. There are V-shaped
205 emissions both near AKR sources at Earth and Saturn, although these are typically filled as
206 opposed to the narrow features in Figure 2. Louis et al. [this issue] shows that some decametric
207 emissions near Perijove 1 have V-shaped emissions that are well modeled by simulations. This
208 suggests the V-shape may be related to sources that are restricted to one or a small set of field
209 lines. Future work will include modeling the frequency-time structure with tools such as those
210 described by Louis et al. [this issue] and Imai et al. [2017 a, b].
211 While there are few specific spectral features that provide accurate plasma frequencies, it
212 appears that fpe is of order 20 kHz throughout the Jovian polar region, hence, fce >> fpe for at least
213 events B and C. The situation is similar to that at Saturn where the density is so low that there is
214 no need for plasma cavities such as occur over Earth’s auroral regions to meet the fce >> fpe
215 requirement for the cyclotron maser instability.
216 Hess et al. [2008] examine various mechanisms by which electron acceleration events
217 observed by the Galileo plasma instrument near Io might generate CMI emissions. Provided the
218 plasma density in the source region is sufficiently low that Earth-like plasma cavities are not
219 required, they favor an oblique instability driven by heating which generates emissions with
220 beaming angles that vary along the Io flux tube with smaller angles at larger magnetic field
221 strengths (lower altitudes, higher frequencies). While the emissions reported herein are not Io
222 related, it is likely similar conical beaming occurs.
223 The first examination of radio emissions from low altitude, high latitude with Juno
224 provided an illuminating view of V-shaped frequency-time structures with vertices near fce and
225 sometimes covering virtually the full spectral range from kilometric to decametric frequencies.
226 Juno came at least close to up to five radio sources over about 18 hours near closest approach.
227 For some of the near-source crossings, electron observations at energies of a few to 10’s of keV
228 show loss cone and beam features that are reminiscent of terrestrial auroral kilometric sources.
229 Louarn et al. [2017] provide evidence that the distribution for Event C is sufficient to drive the
230 cyclotron maser instability, consistent with the observed emissions. It remains to model the
231 observed sources, as done by Louis et al. [this issue] for Io related emissions, to show that they
232 can result in the V-shaped frequency-time structures and to further investigate the energetic
233 electron distributions for their ability to drive the radio emissions. These observations, however,
234 serve to confirm that the CMI process is a universal process for the generation of auroral radio
235 emissions..."




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Monday, October 2, 2017

Jupiter events 5 at Juno Waves and other observatories

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With many thanks from Victor Herrero-Arrieta to the Teams at Juno Waves, NASA Planetary Data System, STEREO A,  WIND, and the Tax Payers of the United States of America.

With many thanks, Victor Herrero-Arrieta acknowledges the Nançay Radio Observatory / Unité Scientifique de Nançay of the Observatoire de Paris (USR 704-CNRS, supported by Université d’Orléans, OSUC, and Région Centre in France) for providing access to NDA observations accessible online at http://www.obs-nancay.fr
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Jupiter events at Juno Waves and other observatories :
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-1-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-2-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-3-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-4-at-juno-waves-and.html
http://herrero-radio-astronomy.blogspot.com/2017/10/jupiter-events-5-at-juno-waves-and.html
Jupiter events at the University of Iowa Space Physics LWA1 Data Project :
http://herrero-radio-astronomy.blogspot.com/2017/08/jupiter-events-1-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/08/jupiter-events-2-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-3-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-4-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-5-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-6-at-university-of-iowa.html
http://herrero-radio-astronomy.blogspot.com/2017/09/jupiter-events-7-at-university-of-iowa.html
Examples of Jupiter events observed by Juno Waves :
http://herrero-radio-astronomy.blogspot.com/2017/05/examples-of-jupiter-events-observed-by.html
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Jupiter 160826 at Juno Waves, STEREO A, WIND, Paris Observatory :
 


Jupiter 161210 at Juno Waves and Long Wavelength Array :

Jupiter 170123 at Juno Waves and LWA1 :


With many thanks to Jeremy Faden and Chris Piker, University of Iowa Autoplot Project, Juno Waves perijoves 160827 161211 170202, 7E1 to 4.1E7 hertz :









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