ALBERT

Description: We simulate and compare three phases of the Mars-solar wind interaction with the 8 March interplanetary coronal mass ejection (ICME) event using Mars Atmosphere and Volatile EvolutioN (MAVEN) mission observations in order to derive heavy ion precipitation and escape rates. The MAVEN observations provide the initial conditions for three steady state MHD model cases, which reproduce the observed features in the solar wind density, velocity, and magnetic field seen along the MAVEN orbit. Applying the MHD results to a kinetic test particle model, we simulate global precipitation and escape maps of O + during the (1) pre-ICME phase, (2) sheath phase, and (3) ejecta phase. We find that the Case 1 had the lowest precipitation and escape rates of 9.5 × 10 25 and 4.1 × 10 25  s −1 , Case 2 had the highest rates of 9.5 × 10 25 and 4.1 × 10 25  s −1 , and Case 3 had rates of 3.2 × 10 25 and 1.3 × 10 25  s −1 , respectively. Additionally, Case 2 produced a high-energy escaping plume 〉10 keV, which mirrored corresponding STATIC observations.

Description: Mars is typically viewed as a member of the category of weakly magnetized planets, with a largely induced magnetosphere and magnetotail produced by the draped fields of the solar wind interaction. However, selected MAVEN suprathermal electron and magnetic field observations in the near wake, sampled along its elliptical orbit during the early prime mission at altitudes ranging from its ~150 km periapsis to the tail magnetosheath, reinforce a picture seen in an MHD model where magnetic fields are rooted in the planet throughout much of the Martian magnetotail.

Description: In the absence of an intrinsic dipole magnetic field, Mars' O + planetary ions are accelerated by the solar wind. Because of their large gyroradius, a population of these planetary ions can precipitate back into Mars' upper atmosphere with enough energy to eject neutrals into space via collision. This process, referred to as sputtering, may have been a dominant atmospheric loss process during earlier stages of our Sun. Yet until now, a limited number of observations have been possible; Analyzer of Space Plasmas and Energetic Atoms-3/Mars Express observed such a precipitation only during extreme conditions, suggesting that sputtering might be not as intense as theoretically predicted. Here we describe one example of precipitation of heavy ions during quiet solar conditions. Between November 2014 and April 2015, the average precipitating flux is significant and in agreement with predictions. From these measured precipitating fluxes, we estimate that a maximum of 1.0 × 10 24 O/s could have been lost due to sputtering.

Description: Abstract In this work, we study the influence of the September 2017 solar event on the precipitating heavy ion fluxes toward Mars' atmosphere as seen by Mars Atmosphere and Volatile EvolutioN/Solar Wind Ion Analyzer, an energy and angular ion spectrometer and by Mars Atmosphere and Volatile EvolutioN/Suprathermal and Thermal Ion Composition instrument, an energy, mass, and angular ion spectrometer. After a careful reconstruction of the background induced by the Solar Energetic Particle event in the Mars Atmosphere and Volatile EvolutioN/Solar Wind Ion Analyzer spectrometer, we investigate the precipitating ion flux responses to the space weather events that took place in September 2017. This period is a unique opportunity to analyze the respective role of various possible drivers of heavy ion precipitation into Mars' atmosphere with a wide range of different space weather events occurring during the same month. This study shows an increase in the precipitation flux by more than 1 order of magnitude during the arrival of the September Interplanetary Coronal Mass Ejection compared to the average flux during quiet solar conditions. We also showed that among the possible solar drivers, the solar wind dynamic pressure is the most significant during September 2017.

Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Connerney, Jack -- England -- Nature. 2013 Apr 11;496(7444):178-9. doi: 10.1038/496178a.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Planetary Magnetospheres Laboratory, Goddard Space Flight Center, National Aeronautics and Space Administration, Code 695, Greenbelt, Maryland 20771, USA. jack.connerney@nasa.gov〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/23579675" target="_blank"〉PubMed〈/a〉

Description: The Mars Atmosphere and Volatile Evolution (MAVEN) mission, during the second of its Deep Dip campaigns, made comprehensive measurements of martian thermosphere and ionosphere composition, structure, and variability at altitudes down to ~130 kilometers in the subsolar region. This altitude range contains the diffusively separated upper atmosphere just above the well-mixed atmosphere, the layer of peak extreme ultraviolet heating and primary reservoir for atmospheric escape. In situ measurements of the upper atmosphere reveal previously unmeasured populations of neutral and charged particles, the homopause altitude at approximately 130 kilometers, and an unexpected level of variability both on an orbit-to-orbit basis and within individual orbits. These observations help constrain volatile escape processes controlled by thermosphere and ionosphere structure and variability.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Bougher, S -- Jakosky, B -- Halekas, J -- Grebowsky, J -- Luhmann, J -- Mahaffy, P -- Connerney, J -- Eparvier, F -- Ergun, R -- Larson, D -- McFadden, J -- Mitchell, D -- Schneider, N -- Zurek, R -- Mazelle, C -- Andersson, L -- Andrews, D -- Baird, D -- Baker, D N -- Bell, J M -- Benna, M -- Brain, D -- Chaffin, M -- Chamberlin, P -- Chaufray, J-Y -- Clarke, J -- Collinson, G -- Combi, M -- Crary, F -- Cravens, T -- Crismani, M -- Curry, S -- Curtis, D -- Deighan, J -- Delory, G -- Dewey, R -- DiBraccio, G -- Dong, C -- Dong, Y -- Dunn, P -- Elrod, M -- England, S -- Eriksson, A -- Espley, J -- Evans, S -- Fang, X -- Fillingim, M -- Fortier, K -- Fowler, C M -- Fox, J -- Groller, H -- Guzewich, S -- Hara, T -- Harada, Y -- Holsclaw, G -- Jain, S K -- Jolitz, R -- Leblanc, F -- Lee, C O -- Lee, Y -- Lefevre, F -- Lillis, R -- Livi, R -- Lo, D -- Ma, Y -- Mayyasi, M -- McClintock, W -- McEnulty, T -- Modolo, R -- Montmessin, F -- Morooka, M -- Nagy, A -- Olsen, K -- Peterson, W -- Rahmati, A -- Ruhunusiri, S -- Russell, C T -- Sakai, S -- Sauvaud, J-A -- Seki, K -- Steckiewicz, M -- Stevens, M -- Stewart, A I F -- Stiepen, A -- Stone, S -- Tenishev, V -- Thiemann, E -- Tolson, R -- Toublanc, D -- Vogt, M -- Weber, T -- Withers, P -- Woods, T -- Yelle, R -- New York, N.Y. -- Science. 2015 Nov 6;350(6261):aad0459. doi: 10.1126/science.aad0459.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉CLaSP Department, University of Michigan, Ann Arbor, MI, USA. bougher@umich.edu. ; Laboratory for Atmospheric and Space Physics, University. of Colorado, Boulder, CO, USA. ; Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA. ; NASA/Goddard Space Flight Center, Greenbelt, MD, USA. ; Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA, USA. ; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. ; CNRS/Institut de Recherche en Astrophysique et Planetologie, Toulouse, France. University Paul Sabatier, Toulouse, France. ; Swedish Institute of Space Physics, Kiruna, Sweden. ; NASA/Johnson Space Center, Houston, TX, USA. ; National Institute of Aerospace, Hampton, VA, USA. ; Laboratoire Atmospheres, Milieux, Observations Spatiales /CNRS, Verrieres-le-Buisson, France. ; Department of Astronomy, Boston University, Boston, MA, USA. ; CLaSP Department, University of Michigan, Ann Arbor, MI, USA. ; Department of Physics and Astronomy, University of Kansas, Lawrence, KS, USA. ; Computational Physics, Springfield, VA, USA. ; Department of Physics, Wright State University, Fairborn, OH, USA. ; Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ, USA. ; Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA, USA. ; Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, Aichi, Japan. ; Naval Research Laboratory, Washington, DC, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26542579" target="_blank"〉PubMed〈/a〉

Description: Coupling between the lower and upper atmosphere, combined with loss of gas from the upper atmosphere to space, likely contributed to the thin, cold, dry atmosphere of modern Mars. To help understand ongoing ion loss to space, the Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft made comprehensive measurements of the Mars upper atmosphere, ionosphere, and interactions with the Sun and solar wind during an interplanetary coronal mass ejection impact in March 2015. Responses include changes in the bow shock and magnetosheath, formation of widespread diffuse aurora, and enhancement of pick-up ions. Observations and models both show an enhancement in escape rate of ions to space during the event. Ion loss during solar events early in Mars history may have been a major contributor to the long-term evolution of the Mars atmosphere.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Jakosky, B M -- Grebowsky, J M -- Luhmann, J G -- Connerney, J -- Eparvier, F -- Ergun, R -- Halekas, J -- Larson, D -- Mahaffy, P -- McFadden, J -- Mitchell, D F -- Schneider, N -- Zurek, R -- Bougher, S -- Brain, D -- Ma, Y J -- Mazelle, C -- Andersson, L -- Andrews, D -- Baird, D -- Baker, D -- Bell, J M -- Benna, M -- Chaffin, M -- Chamberlin, P -- Chaufray, Y-Y -- Clarke, J -- Collinson, G -- Combi, M -- Crary, F -- Cravens, T -- Crismani, M -- Curry, S -- Curtis, D -- Deighan, J -- Delory, G -- Dewey, R -- DiBraccio, G -- Dong, C -- Dong, Y -- Dunn, P -- Elrod, M -- England, S -- Eriksson, A -- Espley, J -- Evans, S -- Fang, X -- Fillingim, M -- Fortier, K -- Fowler, C M -- Fox, J -- Groller, H -- Guzewich, S -- Hara, T -- Harada, Y -- Holsclaw, G -- Jain, S K -- Jolitz, R -- Leblanc, F -- Lee, C O -- Lee, Y -- Lefevre, F -- Lillis, R -- Livi, R -- Lo, D -- Mayyasi, M -- McClintock, W -- McEnulty, T -- Modolo, R -- Montmessin, F -- Morooka, M -- Nagy, A -- Olsen, K -- Peterson, W -- Rahmati, A -- Ruhunusiri, S -- Russell, C T -- Sakai, S -- Sauvaud, J-A -- Seki, K -- Steckiewicz, M -- Stevens, M -- Stewart, A I F -- Stiepen, A -- Stone, S -- Tenishev, V -- Thiemann, E -- Tolson, R -- Toublanc, D -- Vogt, M -- Weber, T -- Withers, P -- Woods, T -- Yelle, R -- New York, N.Y. -- Science. 2015 Nov 6;350(6261):aad0210. doi: 10.1126/science.aad0210.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉University of Colorado, Boulder, CO, USA. bruce.jakosky@lasp.colorado.edu. ; NASA/Goddard Space Flight Center, Greenbelt, MD, USA. ; University of California at Berkeley, Berkeley, CA, USA. ; University of Colorado, Boulder, CO, USA. ; University of Iowa, Iowa City, IA, USA. ; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA. ; University of Michigan, Ann Arbor, MI, USA. ; University of California at Los Angeles, Los Angeles, CA, USA. ; CNRS-Institut de Recherche en Astrophysique et Planetologie (IRAP), Toulouse, France. University Paul Sabatier, Toulouse, France. ; Swedish Institute of Space Physics, Uppsala, Sweden. ; NASA/Johnson Space Center, Houston, TX, USA. ; National Institute of Aerospace, Hampton, VA, USA. ; Laboratoire atmospheres, milieux et observations spatiales (LATMOS)-CNRS, Paris, France. ; Boston University, Boston, MA, USA. ; University of Kansas, Lawrence, KS, USA. ; Computational Physics, Inc., Boulder, CO, USA. ; Wright State University, Dayton, OH, USA. ; University of Arizona, Tucson, AZ, USA. ; Nagoya University, Nagoya, Japan. ; Naval Research Laboratory, Washington, DC, USA. ; North Carolina State University, Raleigh, NC, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26542576" target="_blank"〉PubMed〈/a〉

Description: Recent results of the first ever orbit through Jupiter's auroral region by NASA's Juno spacecraft did not show evidence of coherent acceleration in the auroral or polar region. However, in this letter, we show energetic particle data from Juno's JEDI instrument during the third auroral pass that exhibits conclusive evidence of downward parallel electric fields in portions of Jupiter's polar region. The energetic particle distributions show inverted-V ion and electron structures in a downward electric current region with accelerated peaked distributions in the 100s of keV to ~1 MeV range. The origin of these large electric potential structures is investigated and discussed within the current theoretical framework of current-voltage relationships at both Earth and Jupiter. Parallel electric fields responsible for accelerating particles to maintain the aurora/magnetospheric circuit appear to be a common phenomenon among strongly-magnetized planets with conducting ionospheres, however their origin and generation mechanisms are subjects of ongoing research.

Description: We report on the first observations of 100 eV to 100 keV electrons over the auroral regions of Jupiter by the Jovian Auroral Distributions Experiment (JADE) onboard the Juno mission. The focus is on the regions that were magnetically connected to the main auroral oval. Amongst the most remarkable features, JADE observed electron beams, mostly upward going but also some downward going in the south, at latitudes from ~69° to 72° and ~ −66° to −70° corresponding to M-shells (“M” for magnetic) from ~18 to 54 and ~28 to 61, respectively. The beams were replaced by upward loss cones at lower latitudes. There was no evidence of strongly accelerated downward electrons analogous to the auroral “inverted V's” at Earth. Rather, the presence of upward loss cones suggests a diffuse aurora process. The energy spectra resemble tails of distributions or power laws (suggestive of a stochastic acceleration process), but can also have some clear enhancements or even peaks generally between 1 and 10 keV. Electron intensities change on time scales of a second or less at times implying that auroral structures can be of the order of a few tens of km.

Description: A Hot Flow Anomaly (HFA) is created when an interplanetary current sheet interacts with a planetary bow shock. Previous studies have reported observing HFAs at Earth, Mercury, Venus, Mars and Saturn. During Juno's approach to Jupiter, a number of its instruments operated in the solar wind. Prior to crossing into Jupiter's magnetosphere, Juno observed an HFA at Jupiter for the first time. This Jovian HFA shares most of the characteristics of HFAs seen at other planets. The notable exception is that the Jovian HFA is significantly larger than any HFA seen before. With an apparent size greater than 2 × 10 6  km the Jovian HFA is orders of magnitude larger than those seen at the other planets. By comparing the size of the HFAs at the other planets with the Jovian HFA, we conclude that HFAs size scales with the size of planetary bow shocks that the interplanetary current sheet interacts with.