Article
Geosciences, Multidisciplinary
Jiachen Ding, Ping Yang, Mark T. Lemmon, Yuheng Zhang
Summary: The study shows that carbon dioxide ice crystals in the Martian atmosphere can create halos, and a recent halo observed on Mars may be caused by a mixture of water ice crystals and CO2 ice crystals.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Astronomy & Astrophysics
Xiaotong Yun, Song Fu, Binbin Ni, Wei Xu, Xudong Gu, Xing Cao, Xin Ma, Qiong Luo, Man Hua, Zheng Xiang, Hengle Du
Summary: Due to the lack of a global magnetic field on Mars, the charge exchange process between solar wind protons and Martian hydrogen corona plays a critical role in the Martian atmosphere. This study shows that proton cyclotron waves (PCWs) and proton aurorae were simultaneously observed during consecutive orbits, indicating a strong correlation between these two phenomena. The results also suggest that PCWs and proton aurora events occur more frequently and intensively within the stream interaction region, modulated by solar wind activity.
ASTROPHYSICAL JOURNAL
(2022)
Article
Geosciences, Multidisciplinary
Sonal K. Jain, Justin Deighan, Mike Chaffin, Greg Holsclaw, Rob Lillis, Matt Fillingim, J. Scott Evans, John Correira, Hessa AlMatroushi, Fatma Lootah, Scott England, Hoor AlMazmi, Ed Thiemann, Phil Chamberlin, Frank Eparvier
Summary: This study presents the first continuous observations of extreme ultraviolet (EUV) and far ultraviolet (FUV) dayglow emissions on Mars, showing excellent agreement with previous observations. The analysis of approximately 10 months of data reveals day-to-day variations and a correlation between these emissions and solar activity and seasonal changes.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Loic Rossi, Margaux Vals, Franck Montmessin, Francois Forget, Ehouarn Millour, Anna Fedorova, Alexander Trokhimovskiy, Oleg Korablev
Summary: The D/H ratio is commonly used to study the history of water on Mars, however, the mechanisms controlling present-day HDO behavior are not well understood. Ground-based observations confirmed significant variations of the D/H ratio, particularly lower HDO/H2O ratios in colder regions of Mars due to isotopic fractionation during condensation. A study exploring the impact of a global dust storm in Martian year 34 found that HDO was 40% more abundant on average at 100 km during the storm year, potentially leading to significant consequences for the escape flux of water that year.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Zhaopeng Wu, Tao Li, Jing Li, Chengyun Yang, Jun Cui
Summary: Simulation studies have shown the significant thermal effect of water ice clouds on the Martian atmosphere and climate. This work investigates the diurnal variations of water ice on Mars using multi-local time data, revealing a close correlation between thermal tide and water ice diurnal variations. The results suggest a low threshold of tidal amplitude for generating water ice diurnal variations and have implications for understanding the phase transition process in the Martian atmosphere and improving the Martian global climate model.
Article
Geochemistry & Geophysics
Ashraf Farahat, Majd Mayyasi, Paul Withers, Maher A. Dayeh, Abdelgadir Abuelgasim
Summary: The analysis of six neutral species in the Martian upper atmosphere during the 2018 global dust storm revealed changes in the relative abundance of the species at the storm onset, with densities increasing during the storm except for O and He. During the storm, the relative abundances of CO2 and Ar increased, CO and O decreased, and N-2 and He remained the same.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2021)
Article
Optics
P. Kalaitzis, S. Danakas, C. Bordas, S. Cohen
Summary: In this study, we investigated near-threshold atomic photoionization in the presence of an external uniform static electric field. We projected the two-dimensional flux of slow photoelectrons onto a position sensitive detector (PSD) for analysis. The excited Stark states which were ionized were found to be highly dependent on the static field, and the field's presence was necessary for accurately interpreting the recorded images, especially in relation to laser polarization. By conducting a two-photon ionization experiment and changing the angle between the linear ionizing-laser polarization and the field direction, we observed changes in the final Stark states' population and excitation weights.
Article
Astronomy & Astrophysics
Marton Mester
Summary: The oscillations of the Martian Northern Hemisphere polar vortex are examined using the Kida vortex model. The study demonstrates that the vortex is controlled by the Hadley cell and planetary-scale waves, which are directly linked to Martian topography.
Article
Geosciences, Multidisciplinary
Siteng Fan, Francois Forget, Michael D. Smith, Sandrine Guerlet, Khalid M. Badri, Samuel A. Atwood, Roland M. B. Young, Christopher S. Edwards, Philip R. Christensen, Justin Deighan, Hessa R. Al Matroushi, Antoine Bierjon, Jiandong Liu, Ehouarn Millour
Summary: This study analyzes migrating thermal tides in the Martian atmosphere using temperature profiles retrieved from the Emirates Mars InfraRed Spectrometer. The results show the presence of diurnal and semi-diurnal tides, which are consistent with predictions from the Mars Planetary Climate Model. However, there are some discrepancies between the observed and predicted characteristics of these tides.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Siteng Fan, Sandrine Guerlet, Francois Forget, Antoine Bierjon, Ehouarn Millour, Nikolay Ignatiev, Alexey Shakun, Alexey Grigoriev, Alexander Trokhimovskiy, Franck Montmessin, Oleg Korablev
Summary: Thermal tides in the Martian atmosphere are analyzed using temperature profiles retrieved from nadir observations obtained by the TIRVIM Fourier-spectrometer. The results show significant diurnal and semi-diurnal tides near the Martian summer solstice, consistent with model predictions, but with noticeable earlier phases in the observed data.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Optics
D. Habibovic, D. B. Milosevic
Summary: This study investigates the detachment of electrons from negative ions by ultrashort few-cycle laser pulses in the near-infrared spectral region. The differential detachment probability is calculated using either numerical integration or the saddle-point method. The analysis of the photoelectron momentum distribution reveals that it depends significantly on the polarization state of the driving light and the absolute phase value. The control of the momentum distribution can be accurately achieved by manipulating the absolute phase as a control knob, particularly in regions dominated by rescattered electrons.
Article
Chemistry, Physical
Hang Yuan, Shenyue Xu, Enliang Wang, Jiawei Xu, Yue Gao, Xiaolong Zhu, Dalong Guo, Binghui Ma, Dongmei Zhao, Shaofeng Zhang, Shuncheng Yan, Ruitian Zhang, Yong Gao, Zhongfeng Xu, Xinwen Ma
Summary: This article presents a combined experimental and theoretical investigation of the three-body fragmentation dynamics of CO22+ to C+ + O+ + O. Three dissociation mechanisms are identified, with the dominant one being the concerted fragmentation with two C-O bonds breaking simultaneously. The sequential pathway and a novel isomerization pathway are also found to contribute significantly.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Article
Geochemistry & Geophysics
B. Cooper, M. de la Torre Juarez, M. Mischna, M. Lemmon, G. Martinez, D. Kass, A. R. Vasavada, C. Campbell, J. Moores
Summary: Through analyzing REMS temperature data, it is found that atmospheric warming occurs briefly after sunset when clouds are present, but ground temperature remains relatively stable. Clouds persisting overnight seasonally can lead to warming of daily minimum surface temperatures, and the presence and impact of clouds can be clearly discerned in REMS temperature measurements.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2021)
Article
Astronomy & Astrophysics
Y. Dong, D. A. Brain, R. Ramstad, X. Fang, J. P. McFadden, J. S. Halekas, F. Eparvier, J. R. Espley, J. R. Gruesbeck, B. M. Jakosky
Summary: We have analyzed data from the NASA MAVEN mission to understand the relationship between ion escape and solar EUV irradiance on Mars. By dividing the planetary ion data into subsets with different EUV conditions, we found that the total ion escape rate can increase nonlinearly and eventually reach a limit as EUV increases. Further analysis showed that different ion populations have varying dependencies on solar EUV. We also observed variations in ion density and velocity under different EUV conditions, likely caused by changes in electromagnetic field distributions.
Article
Geochemistry & Geophysics
S. A. Crowther, P. L. Clay, S. Edwards, H. Busemann, K. H. Joy, A. A. Early, R. Burgess, A. R. Butcher, M. Humayun, J. D. Gilmour
Summary: The martian meteorite NWA 8114, along with its complex rock and mineral load, provides valuable insights into the evolution of the Martian atmosphere over the past 4 billion years. By analyzing noble gases in the meteorite, researchers were able to develop a model for the evolution of the Martian atmosphere, highlighting changes in xenon isotopic composition over time.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Astronomy & Astrophysics
Z. Girazian, J. Halekas, R. J. Lillis
Summary: Using MAVEN observations, we studied the variations in the structure and composition of the nightside ionosphere on Mars on solar cycle and seasonal timescales. Plasma densities vary significantly at fixed altitudes due to variations in thermospheric pressure levels. The electron impact ionization (EII) rate, influenced by solar cycle and seasonal trends, also affects the nightside densities. High-altitude nightside ionosphere densities vary significantly over the solar cycle, with topside O+ and O+2 densities changing by factors of -50 and -40, respectively. Topside ion densities remained relatively stable during the solar minimum of 2018-2019.
Article
Astronomy & Astrophysics
Beatriz Sanchez-Cano, Mark Lester, David J. Andrews, Hermann Opgenoorth, Robert Lillis, Francois Leblanc, Christopher M. Fowler, Xiaohua Fang, Oleg Vaisberg, Majd Mayyasi, Mika Holmberg, Jingnan Guo, Maria Hamrin, Christian Mazelle, Kerstin Peter, Martin Patzold, Katerina Stergiopoulou, Charlotte Goetz, Vladimir Nikolaevich Ermakov, Sergei Shuvalov, James A. Wild, Pierre-Louis Blelly, Michael Mendillo, Cesar Bertucci, Marco Cartacci, Roberto Orosei, Feng Chu, Andrew J. Kopf, Zachary Girazian, Michael T. Roman
Summary: This White Paper discusses key scientific questions about the dynamics of the Martian plasma system and how they could be addressed through coordinated multi-point missions. It presents specific scientific objectives and proposes two mission concepts based on coordinated multi-point science to focus on understanding and solving current science gaps.
EXPERIMENTAL ASTRONOMY
(2022)
Review
Astronomy & Astrophysics
H. E. S. Amiri, D. Brain, O. Sharaf, P. Withnell, M. McGrath, M. Alloghani, M. Al Awadhi, S. Al Dhafri, O. Al Hamadi, H. Al Matroushi, Z. Al Shamsi, O. Al Shehhi, M. Chaffin, J. Deighan, C. Edwards, N. Ferrington, B. Harter, G. Holsclaw, M. Kelly, D. Kubitschek, B. Landin, R. Lillis, M. Packard, J. Parker, E. Pilinski, B. Pramman, H. Reed, S. Ryan, C. Sanders, M. Smith, C. Tomso, R. Wrigley, H. Al Mazmi, N. Al Mheiri, M. Al Shamsi, E. Al Tunaiji, K. Badri, P. Christensen, S. England, M. Fillingim, F. Forget, S. Jain, B. M. Jakosky, A. Jones, F. Lootah, J. G. Luhmann, M. Osterloo, M. Wolff, M. Yousuf
Summary: The Emirates Mars Mission (EMM) is the first interplanetary spacecraft mission undertaken by the United Arab Emirates (UAE). It aims to gather scientifically useful information about Mars through global remote sensing measurements. The mission faced tight schedule and cost constraints, but a team of Emirati and American engineers successfully developed and launched a fully functional spacecraft. EMM is being operated from the UAE and the United States (U.S.), and its data will be freely available.
SPACE SCIENCE REVIEWS
(2022)
Article
Geosciences, Multidisciplinary
Shaosui Xu, David L. Mitchell, James P. McFadden, Nicholas M. Schneider, Zachariah Milby, Sonal Jain, Tristan Weber, David A. Brain, Gina A. DiBraccio, Jasper Halekas, Suranga Ruhunusiri, Christian Mazelle, Robert J. Lillis, Ben Johnston
Summary: This study establishes empirical criteria and enables a direct statistical comparison between discrete aurorae and their source electron events, bridging the gap in previous research and facilitating collaboration among different Mars missions and comparative planetary studies of discrete aurora.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Kotaro Sakakura, Kanako Seki, Shotaro Sakai, Ryoya Sakata, Hiroyuki Shinagawa, David A. Brain, James P. McFadden, Jasper S. Halekas, Gina A. DiBraccio, Bruce M. Jakosky, Naoki Terada, Takashi Tanaka
Summary: Based on observations and numerical models, this study investigated the formation mechanism of a molecular ion plume on Mars and its contribution to ion escape. The results show that the plume is formed by the deep penetration of the solar wind-induced electric field under strong solar wind dynamic pressure conditions. This study also found that CO2+ plume events tend to occur under high solar wind dynamic pressure and strong electric field conditions, while O-2(+) plumes can be formed even under weak solar wind conditions.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Geosciences, Multidisciplinary
Robert J. Lillis, Justin Deighan, David Brain, Matthew Fillingim, Sonal Jain, Michael Chaffin, Scott England, Greg Holsclaw, Krishnaprasad Chirakkil, Hessa Al Matroushi, Fatma Lootah, Hoor Al Mazmi, Ed Thiemann, Frank Eparvier, Nick Schneider, Shannon Curry
Summary: This study presents the first measurements and observations of discrete aurora on Mars in the extreme ultraviolet and far ultraviolet ranges. The results reveal that auroral emissions are commonly detected on the nightside images and exhibit visible patterns shifting within a short timeframe. The occurrence of aurora is found to be most frequent in regions of open magnetic topology, with the brightest aurora observed where crustal magnetic fields are strongest. The study also categorizes the discrete auroral morphology into three types and presents the first disk-averaged spectrum of discrete aurora.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Fatma Hussain Lootah, Justin Deighan, Matthew Fillingim, Sonal Jain, J. Scott Evans, Hessa Al Matroushi, Michael Chaffin, Gregory Holsclaw, Robert Lillis, Hour Al Mazmi, John Correira, Scott England
Summary: The Emirates Mars Ultraviolet Spectrometer (EMUS), a far ultraviolet spectrometer on-board the Emirates Mars Mission's (EMM), examines neutral species in the Martian thermosphere and exosphere. This study investigates the emission characteristics of argon and oxygen under different conditions and compares them with data from Earth orbiting observatories.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Michael S. Chaffin, Christopher M. Fowler, Justin Deighan, Sonal Jain, Greg Holsclaw, Andrea Hughes, Robin Ramstad, Yaxue Dong, Dave Brain, Hoor AlMazmi, Krishnaprasad Chirakkil, John Correira, Scott England, J. Scott Evans, Matt Fillingim, Rob Lillis, Fatma Lootah, Susarla Raghuram, Jim McFadden, Jasper Halekas, Jared Espley, Nick Schneider, Majd Mayyasi, Christina O. Lee, Shannon Curry, Hessa AlMatroushi
Summary: Multiple definitive observations of localized patchy proton aurora at Mars are reported in this study, along with the characterization of the plasma environment using measurements from other missions. Multiple mechanisms are required to explain these observations, and further research is needed to understand the impact of these auroral events on Mars atmospheric evolution.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Shaosui Xu, David L. Mitchell, James P. McFadden, Christopher M. Fowler, Kathleen Hanley, Tristan Weber, David A. Brain, Gina A. DiBraccio, Michael W. Liemohn, Robert J. Lillis, Jasper S. Halekas, Suranga Ruhunusiri, Laila Andersson, Christian Mazelle, Shannon M. Curry
Summary: Discrete aurorae have been observed at Mars, and the occurrence rate is found to be influenced by upstream dynamic pressure and interplanetary magnetic field strength. Strong crustal fields are associated with more frequent and intense auroral electron precipitation. This precipitation has significant impact on ionization and plasma density locally.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Astronomy & Astrophysics
R. D. Jolitz, A. Rahmati, D. A. Brain, C. O. Lee, R. J. Lillis, E. Thiemann, F. Eparvier, D. Mitchell, J. Halekas, D. Larson, S. M. Curry, B. M. Jakosky
Summary: Solar extreme ultraviolet (EUV) radiation, solar wind, and solar energetic particles (SEPs) are sources of ionization and heating to the Martian atmosphere. MAVEN's orbit allows it to measure these solar drivers upstream of Mars. By averaging observations over several months, the study found that EUV and solar wind ions are the dominant contributors to energy fluxes, while SEPs play a smaller role. The study also identified the presence of strong and weak coronal mass ejections, which can impact the energy fluxes on the nightside.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Geosciences, Multidisciplinary
H. Madanian, N. Omidi, D. G. Sibeck, L. Andersson, R. Ramstad, S. Xu, J. R. Gruesbeck, S. J. Schwartz, R. A. Frahm, D. A. Brain, P. Kajdic, F. G. Eparvier, D. L. Mitchell, S. M. Curry
Summary: This study investigates the non-planarity of Mars' bow shock and its impact on transient structures near the upstream edge of moving foreshocks caused by slow rotations in the IMF. The structures exhibit a decrease in plasma density and IMF strength within their core, accompanied by a compressional shock layer, consistent with foreshock bubbles. The ion populations responsible for these structures include backstreaming ions and reflected ions with hybrid trajectories.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Astronomy & Astrophysics
Shaosui Xu, David L. L. Mitchell, James P. P. McFadden, Christopher M. M. Fowler, Kathleen Hanley, Tristan Weber, David A. A. Brain, Yingjuan Ma, Gina A. A. DiBraccio, Christian Mazelle, Shannon M. M. Curry
Summary: This study utilizes observations from the MAVEN mission to revisit boundaries within the interaction of Mars and the solar wind, proposing new findings regarding the photoelectron boundary (PEB). It is found that the PEB falls within the ion composition boundary and is not a pressure balance boundary. The PEB marks the top of the Mars dayside ionosphere and serves as the interface where the sheath plasma flow deflects around the obstacle going downstream.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Astronomy & Astrophysics
Wenyi Sun, Yingjuan Ma, Christopher T. Russell, Janet Luhmann, Andrew Nagy, David Brain
Summary: Although photochemistry-enabled escape of oxygen is dominant at Mars today, ion outflow, including planetary proton loss, plays an important role in the atmosphere's long-term evolution. Improving the MHD model of Mars to differentiate between planetary and solar wind protons, we find that planetary proton escape rates exceed heavy ion loss rates and solar wind proton inflows. However, the contribution of planetary protons to hydrogen loss is limited. By considering different reactions, we conclude that H-O charge exchange affects low altitude densities while impact ionizations impact escape rates at higher altitudes. This research highlights the need to include specific treatment of proton origins in future studies on the fate of water on Mars.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
