Found 407 results
Author Title Type [ Year(Asc)]
2019
Authors: Pacheco D., Agueda N., Aran A., Heber B., and Lario D.
Title: Full inversion of solar relativistic electron events measured by the Helios spacecraft
Abstract:

Context. The Parker Solar Probe and the incoming Solar Orbiter mission will provide measurements of solar energetic particle (SEP) events at close heliocentric distances from the Sun. Up to present, the largest data set of SEP events in the inner heliosphere are the observations by the two Helios spacecraft.

Aims. We re-visit a sample of 15 solar relativistic electron events measured by the Helios mission with the goal of better characterising the injection histories of solar energetic particles and their interplanetary transport conditions at heliocentric distances <1 AU.

Methods. The measurements provided by the E6 instrument on board Helios provide us with the electron directional distributions in eight different sectors that we use t. . .
Date: 01/2019 Publisher: Astronomy & Astrophysics Pages: A3 DOI: 10.1051/0004-6361/201834520 Available at: https://www.aanda.org/10.1051/0004-6361/201834520/pdf
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Authors: Pacheco D., Agueda N., Aran A., Heber B., and Lario D.
Title: Full inversion of solar relativistic electron events measured by the Helios spacecraft
Abstract:

Context. The Parker Solar Probe and the incoming Solar Orbiter mission will provide measurements of solar energetic particle (SEP) events at close heliocentric distances from the Sun. Up to present, the largest data set of SEP events in the inner heliosphere are the observations by the two Helios spacecraft.

Aims. We re-visit a sample of 15 solar relativistic electron events measured by the Helios mission with the goal of better characterising the injection histories of solar energetic particles and their interplanetary transport conditions at heliocentric distances <1 AU.

Methods. The measurements provided by the E6 instrument on board Helios provide us with the electron directional distributions in eight different sectors that we use to infe. . .
Date: 01/2019 Publisher: Astronomy & Astrophysics Pages: A3 DOI: 10.1051/0004-6361/201834520 Available at: https://www.aanda.org/10.1051/0004-6361/201834520/pdf
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Authors: Bale S. D., Badman S. T., Bonnell J. W., Bowen T. A., Burgess D., et al.
Title: Highly structured slow solar wind emerging from an equatorial coronal hole
Abstract:

During the solar minimum, when the Sun is at its least active, the solar wind is observed at high latitudes as a predominantly fast (more than 500 kilometres per second), highly Alfvénic rarefied stream of plasma originating from deep within coronal holes. Closer to the ecliptic plane, the solar wind is interspersed with a more variable slow wind of less than 500 kilometres per second. The precise origins of the slow wind streams are less certain; theories and observations suggest that they may originate at the tips of helmet streamers, from interchange reconnection near coronal hole boundaries, or within coronal holes with highly diverging magnetic fields. The heating mechanism required to drive the solar wind is also unresolved, although candidate mechanisms include Alfvé;n-wave tur. . .
Date: 12/2019 Publisher: Nature Pages: 237 - 242 DOI: 10.1038/s41586-019-1818-7 Available at: http://www.nature.com/articles/s41586-019-1818-7
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Authors: Bale S. D., Badman S. T., Bonnell J. W., Bowen T. A., Burgess D., et al.
Title: Highly structured slow solar wind emerging from an equatorial coronal hole
Abstract:

During the solar minimum, when the Sun is at its least active, the solar wind is observed at high latitudes as a predominantly fast (more than 500 kilometres per second), highly Alfvénic rarefied stream of plasma originating from deep within coronal holes. Closer to the ecliptic plane, the solar wind is interspersed with a more variable slow wind of less than 500 kilometres per second. The precise origins of the slow wind streams are less certain; theories and observations suggest that they may originate at the tips of helmet streamers, from interchange reconnection near coronal hole boundaries, or within coronal holes with highly diverging magnetic fields. The heating mechanism required to drive the solar wind is also unresolved, although candidate mechanisms include Alfvé;n-wave tur. . .
Date: 12/2019 Publisher: Nature Pages: 237 - 242 DOI: 10.1038/s41586-019-1818-7 Available at: http://www.nature.com/articles/s41586-019-1818-7
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Authors: Scudder J. D.
Title: The Long-standing Closure Crisis in Coronal Plasmas
Abstract:

Coronal and solar wind physics have long used plasma fluid models to motivate physical explanations of observations; the hypothesized model is introduced into a fluid simulation to see if observations are reproduced. This procedure is called Verification of Mechanism (VoM) modeling; it is contingent on the self consistency of the closure that made the simulation possible. Inner corona VoMs typically assume weak gradient Spitzer-Braginskii closures. Four prominent coronal VoMs in place for decades are shown to contradict their closure hypotheses, demonstrably shaping coronal and solar wind research. These findings have been possible since 1953. This unchallenged evolution is worth understanding, so that similarly flawed VoMs do not continue to mislead new research. As a first step in thi. . .
Date: 11/2019 Publisher: The Astrophysical Journal Pages: 148 DOI: 10.3847/1538-4357/ab48e0 Available at: https://iopscience.iop.org/article/10.3847/1538-4357/ab48e0
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Authors: Scudder J. D.
Title: The Long-standing Closure Crisis in Coronal Plasmas
Abstract:

Coronal and solar wind physics have long used plasma fluid models to motivate physical explanations of observations; the hypothesized model is introduced into a fluid simulation to see if observations are reproduced. This procedure is called Verification of Mechanism (VoM) modeling; it is contingent on the self consistency of the closure that made the simulation possible. Inner corona VoMs typically assume weak gradient Spitzer─Braginskii closures. Four prominent coronal VoMs in place for decades are shown to contradict their closure hypotheses, demonstrably shaping coronal and solar wind research. These findings have been possible since 1953. This unchallenged evolution is worth understanding, so that similarly flawed VoMs do not continue to mislead new research. As a first step in t. . .
Date: 11/2019 Publisher: The Astrophysical Journal Pages: 148 DOI: 10.3847/1538-4357/ab48e0 Available at: https://iopscience.iop.org/article/10.3847/1538-4357/ab48e0
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Authors: Chang Qing, Xu Xiaojun, Xu Qi, Zhong Jun, Xu Jiaying, et al.
Title: Multiple-point Modeling the Parker Spiral Configuration of the Solar Wind Magnetic Field at the Solar Maximum of Solar Cycle 24
Abstract:

By assuming that the solar wind flow is spherically symmetric and that the flow speed becomes constant beyond some critical distance r = R 0 (neglecting solar gravitation and acceleration by high coronal temperature), the large-scale solar wind magnetic field lines are distorted into a Parker spiral configuration, which is usually simplified to an Archimedes spiral. Using magnetic field observations near Mercury, Venus, and Earth during solar maximum of Solar Cycle 24, we statistically surveyed the Parker spiral angles and obtained the empirical equations of the Archimedes and Parker spirals by fitting the multiple-point results. We found that the solar wind magnetic field configurations are slightly different during different years. Archimedes and Parker spiral configuration. . .
Date: 10/2019 Publisher: The Astrophysical Journal Pages: 102 DOI: 10.3847/1538-4357/ab412a Available at: https://iopscience.iop.org/article/10.3847/1538-4357/ab412
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Authors: Chang Qing, Xu Xiaojun, Xu Qi, Zhong Jun, Xu Jiaying, et al.
Title: Multiple-point Modeling the Parker Spiral Configuration of the Solar Wind Magnetic Field at the Solar Maximum of Solar Cycle 24
Abstract:

By assuming that the solar wind flow is spherically symmetric and that the flow speed becomes constant beyond some critical distance r = R 0 (neglecting solar gravitation and acceleration by high coronal temperature), the large-scale solar wind magnetic field lines are distorted into a Parker spiral configuration, which is usually simplified to an Archimedes spiral. Using magnetic field observations near Mercury, Venus, and Earth during solar maximum of Solar Cycle 24, we statistically surveyed the Parker spiral angles and obtained the empirical equations of the Archimedes and Parker spirals by fitting the multiple-point results. We found that the solar wind magnetic field configurations are slightly different during different years. Archimedes and Parker spiral configuration. . .
Date: 10/2019 Publisher: The Astrophysical Journal Pages: 102 DOI: 10.3847/1538-4357/ab412a Available at: https://iopscience.iop.org/article/10.3847/1538-4357/ab412
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Authors: Howard R. A., Vourlidas A., Bothmer V., Colaninno R. C., DeForest C. E., et al.
Title: Near-Sun observations of an F-corona decrease and K-corona fine structure
Abstract:

Remote observations of the solar photospheric light scattered by electrons (the K-corona) and dust (the F-corona or zodiacal light) have been made from the ground during eclipses and from space at distances as small as 0.3 astronomical units to the Sun. Previous observations of dust scattering have not confirmed the existence of the theoretically predicted dust-free zone near the Sun. The transient nature of the corona has been well characterized for large events, but questions still remain (for example, about the initiation of the corona and the production of solar energetic particles) and for small events even its structure is uncertain. Here we report imaging of the solar corona during the first two perihelion passes (0.16-0.25 astronomical units) of the Parker Solar Probe spacecraft. . .
Date: 12/2019 Publisher: Nature Pages: 232 - 236 DOI: 10.1038/s41586-019-1807-x Available at: http://www.nature.com/articles/s41586-019-1807-x
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Authors: Howard R. A., Vourlidas A., Bothmer V., Colaninno R. C., DeForest C. E., et al.
Title: Near-Sun observations of an F-corona decrease and K-corona fine structure
Abstract:

Remote observations of the solar photospheric light scattered by electrons (the K-corona) and dust (the F-corona or zodiacal light) have been made from the ground during eclipses and from space at distances as small as 0.3 astronomical units to the Sun. Previous observations of dust scattering have not confirmed the existence of the theoretically predicted dust-free zone near the Sun. The transient nature of the corona has been well characterized for large events, but questions still remain (for example, about the initiation of the corona and the production of solar energetic particles) and for small events even its structure is uncertain. Here we report imaging of the solar corona during the first two perihelion passes (0.16-0.25 astronomical units) of the Parker Solar Probe spacecraft. . .
Date: 12/2019 Publisher: Nature Pages: 232 - 236 DOI: 10.1038/s41586-019-1807-x Available at: http://www.nature.com/articles/s41586-019-1807-x
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Authors: Riley Pete, Downs Cooper, Linker Jon A., Mikic Zoran, Lionello Roberto, et al.
Title: Predicting the Structure of the Solar Corona and Inner Heliosphere during Parker Solar Probe ’s First Perihelion Pass
Abstract:

NASA’s Parker Solar Probe (PSP) spacecraft reached its first perihelion of 35.7 solar radii on 2018 November 5. To aid in mission planning, and in anticipation of the unprecedented measurements to be returned, in late October, we developed a three-dimensional magnetohydrodynamic (MHD) solution for the solar corona and inner heliosphere, driven by the then available observations of the Sun’s photospheric magnetic field. Our model incorporates a wave-turbulence-driven model to heat the corona. Here, we present our predictions for the structure of the solar corona and the likely in situ measurements that PSP will be returning over the next few months. We infer that, in the days prior to first encounter, PSP was immersed in wind emanating from a well-established, positive-polarity north. . .
Date: 04/2019 Publisher: The Astrophysical Journal Pages: L15 DOI: 10.3847/2041-8213/ab0ec3 Available at: http://stacks.iop.org/2041-8205/874/i=2/a=L15?key=crossref.94a3f13ef95cab063c2cc60115d0f410http://stacks.iop.org/2041-8205/874/i=2/a=L15/pd
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Authors: Riley Pete, Downs Cooper, Linker Jon A., Mikic Zoran, Lionello Roberto, et al.
Title: Predicting the Structure of the Solar Corona and Inner Heliosphere during Parker Solar Probe 's First Perihelion Pass
Abstract:

NASA’s Parker Solar Probe (PSP) spacecraft reached its first perihelion of 35.7 solar radii on 2018 November 5. To aid in mission planning, and in anticipation of the unprecedented measurements to be returned, in late October, we developed a three-dimensional magnetohydrodynamic (MHD) solution for the solar corona and inner heliosphere, driven by the then available observations of the Sun’s photospheric magnetic field. Our model incorporates a wave-turbulence-driven model to heat the corona. Here, we present our predictions for the structure of the solar corona and the likely in situ measurements that PSP will be returning over the next few months. We infer that, in the days prior to first encounter, PSP was immersed in wind emanating from a well-established, positive-polarity north. . .
Date: 04/2019 Publisher: The Astrophysical Journal Pages: L15 DOI: 10.3847/2041-8213/ab0ec3 Available at: http://stacks.iop.org/2041-8205/874/i=2/a=L15?key=crossref.94a3f13ef95cab063c2cc60115d0f410http://stacks.iop.org/2041-8205/874/i=2/a=L15/pd
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Authors: McComas D. J., Christian E. R., Cohen C. M. S., Cummings A. C., Davis A. J., et al.
Title: Probing the energetic particle environment near the Sun
Abstract:

NASA's Parker Solar Probe mission recently plunged through the inner heliosphere of the Sun to its perihelia, about 24 million kilometres from the Sun. Previous studies farther from the Sun (performed mostly at a distance of 1 astronomical unit) indicate that solar energetic particles are accelerated from a few kiloelectronvolts up to near-relativistic energies via at least two processes: "impulsive" events, which are usually associated with magnetic reconnection in solar flares and are typically enriched in electrons, helium-3 and heavier ions, and "gradual" events, which are typically associated with large coronal-mass-ejection-driven shocks and compressions moving through the corona and inner solar wind and are the dominant source of protons with energies between 1 and 10 megaelectro. . .
Date: 12/2019 Publisher: Nature Pages: 223 - 227 DOI: 10.1038/s41586-019-1811-1 Available at: http://www.nature.com/articles/s41586-019-1811-1
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Authors: McComas D. J., Christian E. R., Cohen C. M. S., Cummings A. C., Davis A. J., et al.
Title: Probing the energetic particle environment near the Sun
Abstract:

NASA’s Parker Solar Probe mission recently plunged through the inner heliosphere of the Sun to its perihelia, about 24 million kilometres from the Sun. Previous studies farther from the Sun (performed mostly at a distance of 1 astronomical unit) indicate that solar energetic particles are accelerated from a few kiloelectronvolts up to near-relativistic energies via at least two processes: "impulsive" events, which are usually associated with magnetic reconnection in solar flares and are typically enriched in electrons, helium-3 and heavier ions, and "gradual" events, which are typically associated with large coronal-mass-ejection-driven shocks and compressions moving through the corona and inner solar wind and are the dominant source of protons with energies between 1 and 10 megaelect. . .
Date: 12/2019 Publisher: Nature Pages: 223 - 227 DOI: 10.1038/s41586-019-1811-1 Available at: http://www.nature.com/articles/s41586-019-1811-1
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Authors: Hein Andreas M., Perakis Nikolaos, Eubanks Marshall, Hibberd Adam, Crowl Adam, et al.
Title: Project Lyra: Sending a spacecraft to 1I/’Oumuamua (former A/2017 U1), the interstellar asteroid
Abstract:

The first definitely interstellar object 1I/’Oumuamua (previously A/2017 U1) observed in our solar system provides the opportunity to directly study material from an other star system. Can such objects be intercepted? The challenge of reaching the object within a reasonable timeframe is formidable due to its high heliocentric hyperbolic excess velocity of about 26 km/s; much faster than any vehicle yet launched. This paper presents a high-level analysis of potential near-term options for a mission to 1I/’Oumuamua and potential similar objects. Reaching 1I/’Oumuamua via a spacecraft launched in a reasonable timeframe of 5-10 years (launch in 2022-2027) requires an Earth departure hyperbolic excess velocity between 33 and 76 km/s for mission durations between 30 and 5 years, respect. . .
Date: 08/2019 Publisher: Acta Astronautica Pages: 552 - 561 DOI: 10.1016/j.actaastro.2018.12.042 Available at: https://linkinghub.elsevier.com/retrieve/pii/S0094576518317004
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Authors: Hein Andreas M., Perakis Nikolaos, Eubanks Marshall, Hibberd Adam, Crowl Adam, et al.
Title: Project Lyra: Sending a spacecraft to 1I/’Oumuamua (former A/2017 U1), the interstellar asteroid
Abstract:

The first definitely interstellar object 1I/'Oumuamua (previously A/2017 U1) observed in our solar system provides the opportunity to directly study material from an other star system. Can such objects be intercepted? The challenge of reaching the object within a reasonable timeframe is formidable due to its high heliocentric hyperbolic excess velocity of about 26 km/s; much faster than any vehicle yet launched. This paper presents a high-level analysis of potential near-term options for a mission to 1I/'Oumuamua and potential similar objects. Reaching 1I/'Oumuamua via a spacecraft launched in a reasonable timeframe of 5-10 years (launch in 2022-2027) requires an Earth departure hyperbolic excess velocity between 33 and 76 km/s for mission durations between 30 and 5 years, respectively.. . .
Date: 08/2019 Publisher: Acta Astronautica Pages: 552 - 561 DOI: 10.1016/j.actaastro.2018.12.042 Available at: https://linkinghub.elsevier.com/retrieve/pii/S0094576518317004
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Authors: Yoon Peter H., Hwang Junga, Kim Hyangpyo, and Seough Jungjoon
Title: Quasi Thermal Noise Spectroscopy for Van Allen Probes
Abstract:

Quasi thermal fluctuations in the Langmuir/upper-hybrid frequency range are pervasively observed in space plasmas including the radiation belt and the ring current region of inner magnetosphere as well as the solar wind. The quasi thermal noise spectroscopy may be employed in order to determine the electron density and temperature as well as to diagnose the properties of energetic electrons when direct measurements are not available. However, when employing the technique, one must carefully take the spacecraft orientation into account. The present paper takes the upper-hybrid and multiple harmonic—or (n + 1/2)fce—emissions measured by the Van Allen Probes as an example in order to illustrate how the spacecraft antenna geometrical factor can be incorporated into the theore. . .
Date: 04/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2019JA026460 Available at: https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JA026460
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Authors: Yoon Peter H., Hwang Junga, Kim Hyangpyo, and Seough Jungjoon
Title: Quasi Thermal Noise Spectroscopy for Van Allen Probes
Abstract:

Quasi thermal fluctuations in the Langmuir/upper-hybrid frequency range are pervasively observed in space plasmas including the radiation belt and the ring current region of inner magnetosphere as well as the solar wind. The quasi thermal noise spectroscopy may be employed in order to determine the electron density and temperature as well as to diagnose the properties of energetic electrons when direct measurements are not available. However, when employing the technique, one must carefully take the spacecraft orientation into account. The present paper takes the upper-hybrid and multiple harmonic—or (n + 1/2)fce—emissions measured by the Van Allen Probes as an example in order to illustrate how the spacecraft antenna geometrical factor can be incorporated into the theore. . .
Date: 04/2019 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2019JA026460 Available at: https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JA026460
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Authors: Ratmaya Widya, Soudant Dominique, Salmon-Monviola Jordy, Plus Martin, Cochennec-Laureau Nathalie, et al.
Title: Reduced phosphorus loads from the Loire and Vilaine rivers were accompanied by increasing eutrophication in the Vilaine Bay (south Brittany, France)
Abstract:

The evolution of eutrophication parameters (i.e., nutrients and phytoplankton biomass) during recent decades was examined in coastal waters of the Vilaine Bay (VB, France) in relation to changes in the Loire and Vilaine rivers. Dynamic linear models were used to study long-term trends and seasonality of dissolved inorganic nutrient and chlorophyll a concentrations (Chl a) in rivers and coastal waters. For the period 1997-2013, the reduction in dissolved riverine inorganic phosphorus (DIP) concentrations led to the decrease in their Chl a levels. However, while dissolved inorganic nitrogen (DIN) concentrations decreased only slightly in the Vilaine, they increased in the Loire, specifically in summer. Simultaneously, phytoplankton in the VB underwent profound changes with increase in bio. . .
Date: 04/2019 Publisher: Biogeosciences Pages: 1361 - 1380 DOI: 10.5194/bg-16-1361-201910.5194/bg-16-1361-2019-supplement Available at: https://www.biogeosciences.net/16/1361/2019/https://www.biogeosciences.net/16/1361/2019/bg-16-1361-2019.pdfhttps://www.biogeosciences.net/16/1361/2019/bg-16-1361-2019-supplement.pdf
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Authors: Le Fur I, De Wit R, Plus M, Oheix J, Derolez V, et al.
Title: Re-oligotrophication trajectories of macrophyte assemblages in Mediterranean coastal lagoons based on 17-year time-series
Abstract:

No abstract


Date: 01/2019 Publisher: Marine Ecology Progress Series Pages: 13 - 32 DOI: 10.3354/meps12814 Available at: https://www.int-res.com/abstracts/meps/v608/p13-32/https://www.int-res.com/articles/meps_oa/m608p013.pdf
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Authors: Parashar T. N., Cuesta M., and Matthaeus W. H.
Title: Reynolds Number and Intermittency in the Expanding Solar Wind: Predictions Based on Voyager Observations
Abstract:

The large-scale features of the solar wind are examined in order to predict small-scale features of turbulence in unexplored regions of the heliosphere. The strategy is to examine how system size, or effective Reynolds number Re, varies, and then how this quantity influences observable statistical properties, including intermittency properties of solar wind turbulence. The expectation based on similar hydrodynamics scalings is that the kurtosis, of the small-scale magnetic field increments, will increase with increasing Re. Simple theoretical arguments as well as Voyager observations indicate that effective interplanetary turbulence Re decreases with increasing heliocentric distance. The decrease of scale-dependent magnetic increment kurtosis with increasing heliocentric distance is ver. . .
Date: 10/2019 Publisher: The Astrophysical Journal Pages: L57 DOI: 10.3847/2041-8213/ab4a82 Available at: https://iopscience.iop.org/article/10.3847/2041-8213/ab4a82
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Authors: Parashar T. N., Cuesta M., and Matthaeus W. H.
Title: Reynolds Number and Intermittency in the Expanding Solar Wind: Predictions Based on Voyager Observations
Abstract:

The large-scale features of the solar wind are examined in order to predict small-scale features of turbulence in unexplored regions of the heliosphere. The strategy is to examine how system size, or effective Reynolds number Re, varies, and then how this quantity influences observable statistical properties, including intermittency properties of solar wind turbulence. The expectation based on similar hydrodynamics scalings is that the kurtosis, of the small-scale magnetic field increments, will increase with increasing Re. Simple theoretical arguments as well as Voyager observations indicate that effective interplanetary turbulence Re decreases with increasing heliocentric distance. The decrease of scale-dependent magnetic increment kurtosis with increasing heliocentric distance is ver. . .
Date: 10/2019 Publisher: The Astrophysical Journal Pages: L57 DOI: 10.3847/2041-8213/ab4a82 Available at: https://iopscience.iop.org/article/10.3847/2041-8213/ab4a82
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Authors: Verscharen Daniel, Chandran Benjamin D. G., Jeong Seong-Yeop, Salem Chadi S., Pulupa Marc P., et al.
Title: Self-induced Scattering of Strahl Electrons in the Solar Wind
Abstract:

We investigate the scattering of strahl electrons by microinstabilities as a mechanism for creating the electron halo in the solar wind. We develop a mathematical framework for the description of electron-driven microinstabilities and discuss the associated physical mechanisms. We find that an instability of the oblique fast-magnetosonic/whistler (FM/W) mode is the best candidate for a microinstability that scatters strahl electrons into the halo. We derive approximate analytic expressions for the FM/W instability threshold in two different β c regimes, where β c is the ratio of the core electrons’ thermal pressure to the magnetic pressure, and confirm the accuracy of these thresholds through comparison with numerical solutions to the hot-plasma dispersion rela. . .
Date: 12/2019 Publisher: The Astrophysical Journal Pages: 136 DOI: 10.3847/1538-4357/ab4c30 Available at: https://iopscience.iop.org/article/10.3847/1538-4357/ab4c30https://iopscience.iop.org/article/10.3847/1538-4357/ab4c30/
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Authors: Verscharen Daniel, Chandran Benjamin D. G., Jeong Seong-Yeop, Salem Chadi S., Pulupa Marc P., et al.
Title: Self-induced Scattering of Strahl Electrons in the Solar Wind
Abstract:

We investigate the scattering of strahl electrons by microinstabilities as a mechanism for creating the electron halo in the solar wind. We develop a mathematical framework for the description of electron-driven microinstabilities and discuss the associated physical mechanisms. We find that an instability of the oblique fast-magnetosonic/whistler (FM/W) mode is the best candidate for a microinstability that scatters strahl electrons into the halo. We derive approximate analytic expressions for the FM/W instability threshold in two different β c regimes, where β c is the ratio of the core electrons’ thermal pressure to the magnetic pressure, and confirm the accuracy of these thresholds through comparison with numerical solutions to the hot-plasma dispersion rela. . .
Date: 12/2019 Publisher: The Astrophysical Journal Pages: 136 DOI: 10.3847/1538-4357/ab4c30 Available at: https://iopscience.iop.org/article/10.3847/1538-4357/ab4c30https://iopscience.iop.org/article/10.3847/1538-4357/ab4c30/
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Authors: Pecora Francesco, Greco Antonella, Hu Qiang, Servidio Sergio, Chasapis Alexandros G., et al.
Title: Single-spacecraft Identification of Flux Tubes and Current Sheets in the Solar Wind
Abstract:

A novel technique is presented for describing and visualizing the local topology of the magnetic field using single-spacecraft data in the solar wind. The approach merges two established techniques: the Grad-Shafranov (GS) reconstruction method, which provides a plausible regional two-dimensional magnetic field surrounding the spacecraft trajectory, and the Partial Variance of Increments (PVI) technique that identifies coherent magnetic structures, such as current sheets. When applied to one month of Wind magnetic field data at 1 minute resolution, we find that the quasi-two-dimensional turbulence emerges as a sea of magnetic islands and current sheets. Statistical analysis confirms that current sheets associated with high values of PVI are mostly located between and within the GS magne. . .
Date: 08/2019 Publisher: The Astrophysical Journal Pages: L11 DOI: 10.3847/2041-8213/ab32d9 Available at: https://iopscience.iop.org/article/10.3847/2041-8213/ab32d9
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