Article
Astronomy & Astrophysics
O. A. Katushkina, I. I. Baliukin, V. V. Izmodenov, D. B. Alexashov
Summary: This paper explores the possible imprints of secondary interstellar hydrogen atoms created at the heliospheric boundary in full-sky maps of hydrogen fluxes at the Earth's orbit. Using a three-dimensional kinetic model, hydrogen flux maps are calculated for different phases of the solar cycle and energy ranges, revealing specific features during solar minimum conditions. The study shows that the geometry and shape of tails in these flux maps depend on the averaged velocity and kinetic temperatures of the secondary population far from the Sun. These results provide insight into detecting the secondary component of interstellar hydrogen separately from the primary component at 1 AU, which could be important for future space missions exploring the heliospheric boundary.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Christine M. Simpson, Ruediger Pakmor, Christoph Pfrommer, Simon C. O. Glover, Rowan Smith
Summary: In this study, the impact of diffusive cosmic rays (CRs) on the evolution of the interstellar medium (ISM) is explored under varying assumptions of supernova explosion environment. It is found that CR pressure and transport are important factors that strongly influence the ISM's solution state. Observable signatures such as gamma-ray emission and H i gas are also investigated, with the gamma-ray luminosity being consistent with observations but the thickness of the H i gas layer potentially being too compact.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Alec Paulive, Joshua T. Carder, Eric Herbst
Summary: In the interstellar medium, the formation of complex organic molecules largely depends on surface reactions. However, in cold dark clouds, thermal desorption is inefficient due to the lack of thermal energy. Non-thermal desorption, such as cosmic ray sputtering, is an important explanation for the detection of many organic molecules in the gas phase. Model results suggest that sputtering is an efficient and significant factor that should be considered in future chemical models.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
D. N. Kosenko, S. A. Balashev
Summary: HD molecule is abundant in the Universe and can be used to constrain physical parameters. We detected HD in Magellanic Clouds and attempted to measure cosmic ray ionization rate, but the results were limited due to the quality of the spectra.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
A. M. W. Mitchell, G. P. Rowell, S. Celli, S. Einecke
Summary: The study identifies the necessary properties of interstellar clouds and accelerators, produces a ranked shortlist of promising target systems, discusses detection prospects for future facilities, and finds that larger, closer, slightly older interstellar clouds are more likely to produce detectable gamma-ray fluxes.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
O. A. Katushkina, A. Galli, V. V. Izmodenov, D. B. Alexashov
Summary: This paper analysed the interstellar hydrogen flux data measured by the IBEX spacecraft since 2009 and found the best-fit model parameters using a numerical kinetic model. The analysis of temporal variations in the flux ratio suggests that errors in the model predictions may be due to incorrect data processing or missing physical factors.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Johan L. Freiherr von Forstner, Mateja Dumbovi, Christian Moestl, Jingnan Guo, Athanasios Papaioannou, Robert Elftmann, Zigong Xu, Jan Christoph Terasa, Alexander Kollhoff, Robert F. Wimmer-Schweingruber, Javier Rodriguez-Pacheco, Andreas J. Weiss, Juergen Hinterreiter, Tanja Amerstorfer, Maike Bauer, Anatoly Belov, Maria A. Abunina, Timothy Horbury, Emma E. Davies, Helen O'Brien, Robert C. Allen, G. Bruce Andrews, Lars Berger, Sebastian Boden, Ignacio Cernuda Cangas, Sandra Eldrum, Francisco Espinosa Lara, Raul Gomez Herrero, John R. Hayes, George C. Ho, Shrinivasrao R. Kulkarni, W. Jeffrey Lees, Cesar Martin, Glenn M. Mason, Daniel Pacheco, Manuel Prieto Mateo, Ali Ravanbakhsh, Oscar Rodriguez Polo, Sebastian Sanchez Prieto, Charles E. Schlemm, Helmut Seifert, Kush Tyagi, Mahesh Yedla
Summary: This study presents observations of the first coronal mass ejection (CME) observed by the Solar Orbiter spacecraft and the associated Forbush decrease (FD) measured by the High Energy Telescope (HET). The study emphasizes the importance of multi-spacecraft observations and data-based modeling for understanding space weather impacts in the inner heliosphere.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Shuai Fu, Xiaoping Zhang, Lingling Zhao, Ming Wang, Wensai Shang, Pengwei Luo
Summary: Observations show a sustained decline in solar activity since the 1980s, with the recent P-24/25 cycle reaching a hundred-year low. The study also reveals significant variations in ACR intensity between different solar cycles, suggesting a possible correlation with the heliospheric current sheet.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
D. N. Kosenko, S. A. Balashev, P. Noterdaeme, J-K Krogager, R. Srianand, C. Ledoux
Summary: A systematic study of deuterated molecular hydrogen (HD) at high redshift reveals new HD lines associated with known Damped Lyman-alpha systems and measures upper limits on column density. The new detections have similar ratios to previous findings, showing marked differences with measurements in the Galaxy, likely due to varying physical conditions and metallicity between local and high-redshift interstellar media. Cosmic ray ionization rate (CRIR, zeta) shows significant dispersion from a few x 10(-18) s(-1) to a few x 10(-15) s(-1), strongly correlating with UV flux (chi) and showing a physical connection with star-forming regions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Riccardo Franceschi, Steven N. Shore
Summary: In this study, we investigate the ionization of the diffuse interstellar medium by cosmic rays using a Monte Carlo method. Our results show that in inhomogeneous medium, particles can be trapped for a long time, enhancing the ionization of the medium.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Marco Padovani, Andrea Bracco, Vibor Jelic, Daniele Galli, Elena Bellomi
Summary: Taking into account the energy-dependent slope of the Galactic cosmic-ray electron spectrum in the energy range of 100 MeV-50 GeV is essential for interpreting the spatial variations of beta and estimating the average value of B along the line of sight.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Margot Fitz Axen, Julia Speicher, Aimee Hungerford, Chris L. Fryer
Summary: An increasing amount of observational data indicates small-scale anisotropies in cosmic rays, with various models proposed to explain them. The standard diffusion transport methods do not account for transport physics in mediums with finite-scale magnetic field structures. This study introduces a Monte Carlo transport method to investigate the effects of finite-scale magnetic field structures on observed small-scale anisotropies in cosmic rays.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Piotr Bladek, Romana Ratkiewicz
Summary: This study defines the nose of the heliopause and investigates its variations in location. The displacement of the heliopause nose depends on the direction and intensity of the interstellar magnetic field, while the structure of the heliosphere and the shape of the heliopause depend on the 11-year cycle of solar activity.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
I. I. Baliukin, V. V. Izmodenov, D. B. Alexashov
Summary: This article discusses the distribution characteristics and property estimation of high-energy pickup protons in the heliosphere, and investigates the acceleration process of pickup protons from the Sun to the heliospheric termination shock under the action of the heliospheric magnetic field.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
I. I. Baliukin, V. V. Izmodenov, D. B. Alexashov
Summary: This study emphasizes the importance of adiabatic energy change in the inner heliosheath and investigates its effects on pickup protons and ENAs using a kinetic model. The findings show that adiabatic energy change leads to broadening of the pickup proton velocity distribution and significant enhancement of ENA flux.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
D. J. McComas, T. Sharma, E. R. Christian, C. M. S. Cohen, M. I. Desai, M. E. Hill, L. Y. Khoo, W. H. Matthaeus, D. G. Mitchell, F. Pecora, J. S. Rankin, N. A. Schwadron, J. R. Szalay, M. M. Shen, C. R. Braga, P. S. Mostafavi, S. D. Bale
Summary: We report the first direct measurements of the particle and field environments of a coronal mass ejection (CME) leg very close to the Sun using observations from Parker Solar Probe (PSP). The observations showed a complete dropout in low-energy solar energetic ions, while the magnetic field and solar wind plasma did not show significant changes at the boundaries of the dropout. The CME leg was found to be significantly different from the assumed magnetic and plasma structure of CMEs near the Sun and observed in interplanetary CMEs farther out in the solar wind.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Bishwas L. Shrestha, Eric J. Zirnstein, David J. McComas
Summary: In this study, the evolution of polar coronal holes (PCHs) is investigated using high-time resolution ENA flux measurements from IBEX-Hi. The PCHs are identified by ENA spectral indices <1.8. The results show a periodic evolution of the ENA spectral index over the poles, with a slight increase in the surface area with flatter ENA spectra from 2009-2011 and a gradual decrease from 2012-2014. The PCH completely disappears in 2016 and reappears starting in 2017, gradually growing until 2019, showing a clear correlation with the change in the PCH area observed at the Sun.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
J. G. Mitchell, C. M. S. Cohen, T. J. Eddy, C. J. Joyce, J. S. Rankin, M. M. Shen, G. A. de Nolfo, E. R. Christian, D. J. McComas, R. L. McNutt, M. E. Wiedenbeck, N. A. Schwadron, M. E. Hill, A. W. Labrador, R. A. Leske, R. A. Mewaldt, D. G. Mitchell, J. R. Szalay
Summary: Energetic charged particles, including solar energetic particle events, stream and corotating interaction regions, galactic cosmic rays, anomalous cosmic rays, and suprathermal ions, are widely present in the heliosphere. The Integrated Science Investigation of the Sun (IS circle dot IS) on board the Parker Solar Probe measures energetic particles closer to the Sun than any instrument suite in history, providing a unique view of the previously unexplored energetic particle population. To facilitate efficient use of IS circle dot IS data, an online living catalog of energetic particle enhancements observed by the IS circle dot IS instruments has been developed.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Astronomy & Astrophysics
M. A. Dayeh, E. J. Zirnstein, D. J. McComas
Summary: Since its discovery in 2009, the IBEX ENA Ribbon has been extensively studied. It is a circular structure with a width of approximately 20-40 degrees, appearing at energies ranging from 0.5-6 keV. A novel method is presented to determine the boundaries and transverse profile of the Ribbon using sequential time variations of ENA fluxes, providing insight into the underlying processes. The results demonstrate the potential of this method for upcoming ENA measurements.
ASTROPHYSICAL JOURNAL LETTERS
(2023)
Article
Astronomy & Astrophysics
P. Swaczyna, M. Bzowski, S. A. Fuselier, A. Galli, J. Heerikhuisen, M. A. Kubiak, D. J. McComas, E. Mobius, F. Rahmanifard, N. A. Schwadron
Summary: The response of the IBEX-Lo instrument to helium atoms is analyzed using the observations in ESA steps 1-4. The ratios of observed count rates are compared to the mean energy of the interstellar neutral helium atoms estimated using the Warsaw Test Particle Model. The obtained relative responses supplement the laboratory calibration and facilitate in-depth quantitative studies of the interstellar neutral helium signal.
ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES
(2023)
Article
Geosciences, Multidisciplinary
Y. Sarkango, J. R. Szalay, A. R. Poppe, Q. Nenon, P. Kollmann, G. Clark, D. J. McComas
Summary: Using data from Juno spacecraft, we analyzed the distribution of energetic protons within Jupiter's inner magnetosphere. Protons with energies between 10 and 50 keV were found to align with the magnetic field, while those above 200 keV showed pancake-like distributions. These distributions suggest charge exchange or adiabatic acceleration of protons from Jupiter's middle magnetosphere.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Multidisciplinary Sciences
S. D. Bale, J. F. Drake, M. D. McManus, M. I. Desai, S. T. Badman, D. E. Larson, M. Swisdak, T. S. Horbury, N. E. Raouafi, T. Phan, M. Velli, D. J. McComas, C. M. S. Cohen, D. Mitchell, O. Panasenco, J. C. Kasper
Summary: The fast solar wind that fills the heliosphere originates from coronal holes on the Sun and is believed to be accelerated by magnetic reconnection mechanisms such as wave heating and interchange reconnection. Measurements from the Parker Solar Probe provide strong evidence for the interchange reconnection mechanism, showing imprints of supergranulation structure in the solar wind and the presence of magnetic switchbacks and bursty wind streams. Computer simulations support these observations and suggest that the reconnection is collisionless and drives the fast wind through both plasma pressure and radial Alfvenic flow bursts.
Review
Physics, Fluids & Plasmas
O. E. Malandraki, C. M. S. Cohen, J. Giacalone, J. G. Mitchell, R. Chhiber, D. J. McComas, J. Rodriguez-Pacheco, R. F. Wimmer-Schweingruber, G. C. Ho
Summary: Solar energetic particles (SEPs) are accelerated at the Sun and can reach high energies. The lack of in situ measurements inside 1 AU has left many questions unanswered. Additionally, observations of energetic particle intensity enhancements associated with high-speed streams or stream interaction regions (SIRs) have been limited. The Solar Orbiter (SolO) and Parker Solar Probe (PSP) missions have provided unprecedented measurements of these phenomena, revealing unexpected observations that challenge our understanding.
PHYSICS OF PLASMAS
(2023)
Article
Astronomy & Astrophysics
G. Livadiotis, D. J. McComas, E. J. Zirnstein
Summary: This study investigates the thermodynamics of plasma protons in the polar regions of the inner heliosheath (IHS) and its connection with solar activity. Based on the year of energetic neutral atom creation, the thermodynamic parameters of the plasma are characterized and the temperatures are statistically analyzed. Autocorrelation analysis is then performed between the IHS temperature and solar activity using sunspot number and fractional area of polar coronal holes as proxies. The findings demonstrate a high correlation between IHS proton temperatures and sunspot number, as well as a high negative correlation between proton plasma temperature and coronal hole fractional areas.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
Laxman Adhikari, Gary P. Zank, Bingbing Wang, Lingling Zhao, Daniele Telloni, Alex Pitna, Merav Opher, Bishwas Shrestha, David J. McComas, Katariina Nykyri
Summary: This study develops a nearly incompressible magnetohydrodynamic (NI MHD) theory for beta similar to 1 (or beta << 1) plasma, and applies it to the study of solar wind turbulence. The theory accurately describes the majority of 2D turbulence in beta similar to 1 or beta << 1 plasma, while also incorporating the minority of slab turbulence. By coupling the NI MHD turbulence transport equations with three fluid equations, the model is able to successfully predict the behavior of the solar wind turbulence.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
P. Swaczyna, M. Bzowski, J. Heerikhuisen, M. A. Kubiak, F. Rahmanifard, E. J. Zirnstein, S. A. Fuselier, A. Galli, D. J. McComas, E. Mobius, N. A. Schwadron
Summary: In-situ observations of interstellar neutral helium atoms are used to determine the velocity and temperature of the pristine very local interstellar medium (VLISM). The observations are compared with a parameterized model of helium transport in the heliosphere, taking into account filtration processes at the heliospheric boundaries. The derived pristine VLISM parameters provide insights into the interstellar conditions, and a strong correlation between interstellar plasma density and magnetic field strength is demonstrated.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
G. Livadiotis, D. J. Mccomas
Summary: The paper investigates the relationship between plasma heating and its polytropic index, and examines the implications through the transport equation of temperature. It introduces the classification of thermodynamic polytropic processes based on their polytropic index and highlights the role of the adiabatic index in the transport equation of temperature. Furthermore, it presents an alternative method for deriving turbulent heating and explores the significance of the derived connecting relationships in the solar wind plasma in the heliosphere.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
G. Livadiotis, D. J. Mccomas
Summary: In this paper, the transport equation of kappa, a thermodynamic parameter for particle velocity distribution, is developed using the concept of entropy defect. The equation is derived for the specific case of exchanging plasma ions, leading to the decrease in entropy. The application of the transport equation to solar wind plasma protons reveals a decrease in kappa with increasing heliocentric distance, indicating plasmas in non-equilibrium states.
ASTROPHYSICAL JOURNAL
(2023)
Article
Astronomy & Astrophysics
R. K. Bera, F. Fraternale, N. V. Pogorelov, V. Roytershteyn, M. Gedalin, D. J. Mccomas, G. P. Zank
Summary: The role of pickup ions (PUIs) in the solar wind's interaction with the local interstellar medium is investigated. The study utilizes 3D, multifluid simulations to describe the flow of charged particles and the behavior of neutrals. By treating PUIs as a separate fluid and deriving boundary conditions from kinetic simulations of collisionless shocks, the results are found to be more consistent with observational data. These findings have implications for the pressure and cooling of the inner heliosheath plasma, as well as the density and temperature of secondary neutral atoms. Simulation results are validated with New Horizons data.
ASTROPHYSICAL JOURNAL
(2023)
Article
Geosciences, Multidisciplinary
S. A. Fuselier, S. M. Petrinec, K. J. Trattner, K. Llera, J. L. Burch, D. J. Gershman, M. A. Dayeh, N. Schwadron, H. O. Funsten, D. J. Mccomas
Summary: In this study, in situ ion measurements and remote sensing of energetic neutral atoms are combined to determine the geocoronal Hydrogen density at large distances from the Earth. The accuracy of using global models to predict the geocoronal density is evaluated by comparing with observations from the Magnetospheric Multiscale mission. The gas dynamic and magnetohydrodynamic (MHD) models generally agree with the observations, but variations around averages indicate relatively large uncertainties in geocoronal density estimates. Fluctuations in density have minimal impact on the critical ion flux in the Interstellar Boundary Explorer IBEX-Hi energy range.
GEOPHYSICAL RESEARCH LETTERS
(2023)
