Found 407 results
Author Title Type [ Year(Asc)]
2020
Authors: Verniero J. L., Larson D. E., Livi R., Rahmati A., McManus M. D., et al.
Title: Parker Solar Probe Observations of Proton Beams Simultaneous with Ion-scale Waves
Abstract:

Parker Solar Probe (PSP), NASA’s latest and closest mission to the Sun, is on a journey to investigate fundamental enigmas of the inner heliosphere. This paper reports initial observations made by the Solar Probe Analyzer for Ions (SPAN-I), one of the instruments in the Solar Wind Electrons Alphas and Protons instrument suite. We address the presence of secondary proton beams in concert with ion-scale waves observed by FIELDS, the electromagnetic fields instrument suite. We show two events from PSP’s second orbit that demonstrate signatures consistent with wave-particle interactions. We showcase 3D velocity distribution functions (VDFs) measured by SPAN-I during times of strong wave power at ion scales. From an initial instability analysis, we infer that the VDFs departed far enough. . .
Date: 05/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 5 DOI: 10.3847/1538-4365/ab86af Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab86afhttps
More Details

Authors: Verniero J. L., Larson D. E., Livi R., Rahmati A., McManus M. D., et al.
Title: Parker Solar Probe Observations of Proton Beams Simultaneous with Ion-scale Waves
Abstract:

Parker Solar Probe (PSP), NASA's latest and closest mission to the Sun, is on a journey to investigate fundamental enigmas of the inner heliosphere. This paper reports initial observations made by the Solar Probe Analyzer for Ions (SPAN-I), one of the instruments in the Solar Wind Electrons Alphas and Protons instrument suite. We address the presence of secondary proton beams in concert with ion-scale waves observed by FIELDS, the electromagnetic fields instrument suite. We show two events from PSP's second orbit that demonstrate signatures consistent with wave-particle interactions. We showcase 3D velocity distribution functions (VDFs) measured by SPAN-I during times of strong wave power at ion scales. From an initial instability analysis, we infer that the VDFs departed far enough awa. . .
Date: 05/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 5 DOI: 10.3847/1538-4365/ab86af Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab86afhttps
More Details

Authors: Meyer‐Vernet Nicole, and Moncuquet Michel
Title: Plasma Waves in Space: The Importance of Properly Accounting for the Measuring Device
Abstract:

Electric fields are generally measured or calculated using two intuitive assumptions: (1) the electric field equals the voltage divided by the antenna length when the antenna is electromagnetically short (2) the antenna responds best to electric field along its length. Both assumptions are often incorrect for electrostatic fields because they scale as the Debye length or as the electron gyroradius, which may be smaller than the antenna length. Taking into account this little-known fact enables us to complete or correct several recent papers on plasma spontaneous fluctuations in various solar system environments.


Date: 03/2020 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2019JA027723 Available at: https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JA027723
More Details
Authors: Meyer-Vernet Nicole, and Moncuquet Michel
Title: Plasma Waves in Space: The Importance of Properly Accounting for the Measuring Device
Abstract:

Electric fields are generally measured or calculated using two intuitive assumptions: (1) the electric field equals the voltage divided by the antenna length when the antenna is electromagnetically short (2) the antenna responds best to electric field along its length. Both assumptions are often incorrect for electrostatic fields because they scale as the Debye length or as the electron gyroradius, which may be smaller than the antenna length. Taking into account this little-known fact enables us to complete or correct several recent papers on plasma spontaneous fluctuations in various solar system environments.


Date: 03/2020 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1029/2019JA027723 Available at: https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JA027723
More Details
Authors: Malaspina David M., Halekas Jasper, Berčič Laura, Larson Davin, Whittlesey Phyllis, et al.
Title: Plasma Waves near the Electron Cyclotron Frequency in the Near-Sun Solar Wind
Abstract:

Data from the first two orbits of the Sun by Parker Solar Probe reveal that the solar wind sunward of 50 solar radii is replete with plasma waves and instabilities. One of the most prominent plasma wave power enhancements in this region appears near the electron cyclotron frequency (fce). Most of this wave power is concentrated in electric field fluctuations near 0.7 fce and fce, with strong harmonics of both frequencies extending above fce. At least two distinct, often concurrent, wave modes are observed, preliminarily identified as electrostatic whistler-mode waves and electron Bernstein waves. Wave intervals range in duration from a few seconds to hours. Both the amplitudes and number of detections of these near-fce waves increas. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 21 DOI: 10.3847/1538-4365/ab4c3b Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab4c3b
More Details

Authors: Malaspina David M., Halekas Jasper, Berčič Laura, Larson Davin, Whittlesey Phyllis, et al.
Title: Plasma Waves near the Electron Cyclotron Frequency in the Near-Sun Solar Wind
Abstract:

Data from the first two orbits of the Sun by Parker Solar Probe reveal that the solar wind sunward of 50 solar radii is replete with plasma waves and instabilities. One of the most prominent plasma wave power enhancements in this region appears near the electron cyclotron frequency (fce). Most of this wave power is concentrated in electric field fluctuations near 0.7 fce and fce, with strong harmonics of both frequencies extending above fce. At least two distinct, often concurrent, wave modes are observed, preliminarily identified as electrostatic whistler-mode waves and electron Bernstein waves. Wave intervals range in duration from a few seconds to hours. Both the amplitudes and number of detections of these near-fce waves increas. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 21 DOI: 10.3847/1538-4365/ab4c3b Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab4c3b
More Details

Authors: Kim T. K., Pogorelov N. V., Arge C. N., Henney C. J., Jones-Mecholsky S. I., et al.
Title: Predicting the Solar Wind at the Parker Solar Probe Using an Empirically Driven MHD Model
Abstract:

Since its launch on 2018 August 12, Parker Solar Probe (PSP) has completed its first and second orbits around the Sun, having reached down to 35.7 solar radii at each perihelion. In anticipation of the exciting new data at such unprecedented distances, we have simulated the global 3D heliosphere using an MHD model coupled with a semi-empirical coronal model using the best available photospheric magnetograms as input. We compare our heliospheric MHD simulation results with in situ measurements along the PSP trajectory from its launch to the completion of the second orbit, with particular emphasis on the solar wind structure around the first two solar encounters. Furthermore, we show our model prediction for the third perihelion, which occurred on 2019 September 1. Comparison of the MHD r. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 40 DOI: 10.3847/1538-4365/ab58c9 Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab58c9
More Details

Authors: Kim T. K., Pogorelov N. V., Arge C. N., Henney C. J., Jones-Mecholsky S. I., et al.
Title: Predicting the Solar Wind at the Parker Solar Probe Using an Empirically Driven MHD Model
Abstract:

Since its launch on 2018 August 12, Parker Solar Probe (PSP) has completed its first and second orbits around the Sun, having reached down to 35.7 solar radii at each perihelion. In anticipation of the exciting new data at such unprecedented distances, we have simulated the global 3D heliosphere using an MHD model coupled with a semi-empirical coronal model using the best available photospheric magnetograms as input. We compare our heliospheric MHD simulation results with in situ measurements along the PSP trajectory from its launch to the completion of the second orbit, with particular emphasis on the solar wind structure around the first two solar encounters. Furthermore, we show our model prediction for the third perihelion, which occurred on 2019 September 1. Comparison of the MHD r. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 40 DOI: 10.3847/1538-4365/ab58c9 Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab58c9
More Details

Authors: Hibberd Adam, Hein Andreas M., and Eubanks Marshall
Title: Project Lyra: Catching 1I/‘Oumuamua – Mission opportunities after 2024
Abstract:

In October 2017, the first interstellar object within our solar system was discovered. Today designated 1I/'Oumuamua, it shows characteristics that have never before been observed in a celestial body. Due to these characteristics, an in-situ investigation of 1I would be of extraordinary scientific value. Previous studies have demonstrated that a mission to 1I/'Oumuamua is feasible using current and near-term technologies, however, with an anticipated launch date of 2020-2021. This is too soon to be realistic. This paper aims at addressing the question of the feasibility of a mission to 1I/'Oumuamua in 2024 and beyond. Using the OITS trajectory simulation tool, various scenarios are analyzed, including a powered Jupiter flyby and Solar Oberth maneuver, a Jupiter powered flyby, and more c. . .
Date: 05/2020 Publisher: Acta Astronautica Pages: 136 - 144 DOI: 10.1016/j.actaastro.2020.01.018 Available at: https://linkinghub.elsevier.com/retrieve/pii/S0094576520300291
More Details

Authors: Hibberd Adam, Hein Andreas M., and Eubanks Marshall
Title: Project Lyra: Catching 1I/‘Oumuamua – Mission opportunities after 2024
Abstract:

In October 2017, the first interstellar object within our solar system was discovered. Today designated 1I/’Oumuamua, it shows characteristics that have never before been observed in a celestial body. Due to these characteristics, an in-situ investigation of 1I would be of extraordinary scientific value. Previous studies have demonstrated that a mission to 1I/’Oumuamua is feasible using current and near-term technologies, however, with an anticipated launch date of 2020-2021. This is too soon to be realistic. This paper aims at addressing the question of the feasibility of a mission to 1I/’Oumuamua in 2024 and beyond. Using the OITS trajectory simulation tool, various scenarios are analyzed, including a powered Jupiter flyby and Solar Oberth maneuver, a Jupiter powered flyby, and . . .
Date: 05/2020 Publisher: Acta Astronautica Pages: 136 - 144 DOI: 10.1016/j.actaastro.2020.01.018 Available at: https://linkinghub.elsevier.com/retrieve/pii/S0094576520300291
More Details

Authors: Duan Die, Bowen Trevor A., Chen Christopher H. K., Mallet Alfred, He Jiansen, et al.
Title: The Radial Dependence of Proton-scale Magnetic Spectral Break in Slow Solar Wind during PSP Encounter 2
Abstract:

Magnetic field fluctuations in the solar wind are commonly observed to follow a power-law spectrum. Near proton-kinetic scales, a spectral break occurs that is commonly interpreted as a transition to kinetic turbulence. However, this transition is not yet entirely understood. By studying the scaling of the break with various plasma properties, it may be possible to constrain the processes leading to the onset of kinetic turbulence. Using data from the Parker Solar Probe, we measure the proton-scale break over a range of heliocentric distances, enabling a measurement of the transition from inertial to kinetic-scale turbulence under various plasma conditions. We find that the break frequency fb increases as the heliocentric distance r decreases in the slow solar wind following . . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 55 DOI: 10.3847/1538-4365/ab672d Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab672d
More Details

Authors: Duan Die, Bowen Trevor A., Chen Christopher H. K., Mallet Alfred, He Jiansen, et al.
Title: The Radial Dependence of Proton-scale Magnetic Spectral Break in Slow Solar Wind during PSP Encounter 2
Abstract:

Magnetic field fluctuations in the solar wind are commonly observed to follow a power-law spectrum. Near proton-kinetic scales, a spectral break occurs that is commonly interpreted as a transition to kinetic turbulence. However, this transition is not yet entirely understood. By studying the scaling of the break with various plasma properties, it may be possible to constrain the processes leading to the onset of kinetic turbulence. Using data from the Parker Solar Probe, we measure the proton-scale break over a range of heliocentric distances, enabling a measurement of the transition from inertial to kinetic-scale turbulence under various plasma conditions. We find that the break frequency fb increases as the heliocentric distance r decreases in the slow solar wind following . . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 55 DOI: 10.3847/1538-4365/ab672d Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab672d
More Details

Authors: Rouillard Alexis P., Kouloumvakos Athanasios, Vourlidas Angelos, Kasper Justin, Bale Stuart, et al.
Title: Relating Streamer Flows to Density and Magnetic Structures at the Parker Solar Probe
Abstract:

The physical mechanisms that produce the slow solar wind are still highly debated. Parker Solar Probe's (PSP's) second solar encounter provided a new opportunity to relate in situ measurements of the nascent slow solar wind with white-light images of streamer flows. We exploit data taken by the Solar and Heliospheric Observatory, the Solar TErrestrial RElations Observatory (STEREO), and the Wide Imager on Solar Probe to reveal for the first time a close link between imaged streamer flows and the high-density plasma measured by the Solar Wind Electrons Alphas and Protons (SWEAP) experiment. We identify different types of slow winds measured by PSP that we relate to the spacecraft's magnetic connectivity (or not) to streamer flows. SWEAP measured high-density and highly variable plasma wh. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 37 DOI: 10.3847/1538-4365/ab579a Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab579a
More Details

Authors: Rouillard Alexis P., Kouloumvakos Athanasios, Vourlidas Angelos, Kasper Justin, Bale Stuart, et al.
Title: Relating Streamer Flows to Density and Magnetic Structures at the Parker Solar Probe
Abstract:

The physical mechanisms that produce the slow solar wind are still highly debated. Parker Solar Probe’s (PSP’s) second solar encounter provided a new opportunity to relate in situ measurements of the nascent slow solar wind with white-light images of streamer flows. We exploit data taken by the Solar and Heliospheric Observatory, the Solar TErrestrial RElations Observatory (STEREO), and the Wide Imager on Solar Probe to reveal for the first time a close link between imaged streamer flows and the high-density plasma measured by the Solar Wind Electrons Alphas and Protons (SWEAP) experiment. We identify different types of slow winds measured by PSP that we relate to the spacecraft’s magnetic connectivity (or not) to streamer flows. SWEAP measured high-density and highly variable pla. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 37 DOI: 10.3847/1538-4365/ab579a Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab579a
More Details

Authors: Réville Victor, Velli Marco, Panasenco Olga, Tenerani Anna, Shi Chen, et al.
Title: The Role of Alfvén Wave Dynamics on the Large-scale Properties of the Solar Wind: Comparing an MHD Simulation with Parker Solar Probe E1 Data
Abstract:

During Parker Solar Probe's first orbit, the solar wind plasma was observed in situ closer than ever before, the perihelion on 2018 November 6 revealing a flow that is constantly permeated by large-amplitude Alfvénic fluctuations. These include radial magnetic field reversals, or switchbacks, that seem to be a persistent feature of the young solar wind. The measurements also reveal a very strong, unexpected, azimuthal velocity component. In this work, we numerically model the solar corona during this first encounter, solving the MHD equations and accounting for Alfvén wave transport and dissipation. We find that the large-scale plasma parameters are well reproduced, allowing the computation of the solar wind sources at Probe with confidence. We try to understand the dynamical nature o. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 24 DOI: 10.3847/1538-4365/ab4fef Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab4fef
More Details

Authors: Réville Victor, Velli Marco, Panasenco Olga, Tenerani Anna, Shi Chen, et al.
Title: The Role of Alfvén Wave Dynamics on the Large-scale Properties of the Solar Wind: Comparing an MHD Simulation with Parker Solar Probe E1 Data
Abstract:

During Parker Solar Probe’s first orbit, the solar wind plasma was observed in situ closer than ever before, the perihelion on 2018 November 6 revealing a flow that is constantly permeated by large-amplitude Alfvénic fluctuations. These include radial magnetic field reversals, or switchbacks, that seem to be a persistent feature of the young solar wind. The measurements also reveal a very strong, unexpected, azimuthal velocity component. In this work, we numerically model the solar corona during this first encounter, solving the MHD equations and accounting for Alfvén wave transport and dissipation. We find that the large-scale plasma parameters are well reproduced, allowing the computation of the solar wind sources at Probe with confidence. We try to understand the dynamical nature. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 24 DOI: 10.3847/1538-4365/ab4fef Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab4fef
More Details

Authors: Schwadron N. A., Bale S., Bonnell J., Case A., Christian E. R., et al.
Title: Seed Population Preconditioning and Acceleration Observed by the Parker Solar Probe
Abstract:

A series of solar energetic particle (SEP) events was observed by the Integrated Science Investigation of the Sun (IS☉IS) on the Parker Solar Probe (PSP) during the period from 2019 April 18 through 24. The PSP spacecraft was located near 0.48 au from the Sun on Parker spiral field lines that projected out to 1 au within ̃25° of the near-Earth spacecraft. These SEP events, though small compared to historically large SEP events, were among the largest observed thus far in the PSP mission and provide critical information about the space environment inside 1 au during SEP events. During this period, the Sun released multiple coronal mass ejections (CMEs). One of these CMEs observed was initiated on 2019 April 20 at 01:25 UTC, and the interplanetary CME (ICME) propagated out and passed . . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 33 DOI: 10.3847/1538-4365/ab5527 Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab5527
More Details

Authors: Schwadron N. A., Bale S., Bonnell J., Case A., Christian E. R., et al.
Title: Seed Population Preconditioning and Acceleration Observed by the Parker Solar Probe
Abstract:

A series of solar energetic particle (SEP) events was observed by the Integrated Science Investigation of the Sun (IS☉IS) on the Parker Solar Probe (PSP) during the period from 2019 April 18 through 24. The PSP spacecraft was located near 0.48 au from the Sun on Parker spiral field lines that projected out to 1 au within ̃25° of the near-Earth spacecraft. These SEP events, though small compared to historically large SEP events, were among the largest observed thus far in the PSP mission and provide critical information about the space environment inside 1 au during SEP events. During this period, the Sun released multiple coronal mass ejections (CMEs). One of these CMEs observed was initiated on 2019 April 20 at 01:25 UTC, and the interplanetary CME (ICME) propagated out and passed . . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 33 DOI: 10.3847/1538-4365/ab5527 Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab5527
More Details

Authors: Strauss R. D., Dresing N., Kollhoff A., and Brüdern M.
Title: On the Shape of SEP Electron Spectra: The Role of Interplanetary Transport
Abstract:

We address the effect of particle scattering on the energy spectra of solar energetic electron events using (I) an observational and (II) a modeling approach. (I) We statistically study observations of the STEREO spacecraft, using directional electron measurements made with the Solar Electron and Proton Telescope in the range of 45-425 keV. We compare the energy spectra of the anti-Sunward propagating beam with that of the backward-scattered population and find that, on average, the backward-scattered population shows a harder spectrum with the effect being stronger at higher energies. (II) We use a numerical solar energetic particle (SEP) transport model to simulate the effect of particle scattering (both in terms of pitch angle and perpendicular to the mean field) on the spectrum. We . . .
Date: 07/2020 Publisher: The Astrophysical Journal Pages: 24 DOI: 10.3847/1538-4357/ab91b0 Available at: https://iopscience.iop.org/article/10.3847/1538-4357/ab91b0https://iopscience.iop.org/article/10.3847/1538-4357/ab91b0/
More Details

Authors: Strauss R. D., Dresing N., Kollhoff A., and Brüdern M.
Title: On the Shape of SEP Electron Spectra: The Role of Interplanetary Transport
Abstract:

We address the effect of particle scattering on the energy spectra of solar energetic electron events using (I) an observational and (II) a modeling approach. (I) We statistically study observations of the STEREO spacecraft, using directional electron measurements made with the Solar Electron and Proton Telescope in the range of 45-425 keV. We compare the energy spectra of the anti-Sunward propagating beam with that of the backward-scattered population and find that, on average, the backward-scattered population shows a harder spectrum with the effect being stronger at higher energies. (II) We use a numerical solar energetic particle (SEP) transport model to simulate the effect of particle scattering (both in terms of pitch angle and perpendicular to the mean field) on the spectrum. We . . .
Date: 07/2020 Publisher: The Astrophysical Journal Pages: 24 DOI: 10.3847/1538-4357/ab91b0 Available at: https://iopscience.iop.org/article/10.3847/1538-4357/ab91b0https://iopscience.iop.org/article/10.3847/1538-4357/ab91b0/
More Details

Authors: Horbury Timothy S., Woolley Thomas, Laker Ronan, Matteini Lorenzo, Eastwood Jonathan, et al.
Title: Sharp Alfvénic Impulses in the Near-Sun Solar Wind
Abstract:

Measurements of the near-Sun solar wind by the Parker Solar Probe have revealed the presence of large numbers of discrete Alfvénic impulses with an anti-sunward sense of propagation. These are similar to those previously observed near 1 au, in high speed streams over the Sun's poles and at 60 solar radii. At 35 solar radii, however, they are typically shorter and sharper than seen elsewhere. In addition, these spikes occur in "patches" and there are also clear periods within the same stream when they do not occur; the timescale of these patches might be related to the rate at which the spacecraft magnetic footpoint tracks across the coronal hole from which the plasma originated. While the velocity fluctuations associated with these spikes are typically under 100 km s−1, du. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 45 DOI: 10.3847/1538-4365/ab5b15 Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab5b15
More Details

Authors: Horbury Timothy S., Woolley Thomas, Laker Ronan, Matteini Lorenzo, Eastwood Jonathan, et al.
Title: Sharp Alfvénic Impulses in the Near-Sun Solar Wind
Abstract:

Measurements of the near-Sun solar wind by the Parker Solar Probe have revealed the presence of large numbers of discrete Alfvénic impulses with an anti-sunward sense of propagation. These are similar to those previously observed near 1 au, in high speed streams over the Sun’s poles and at 60 solar radii. At 35 solar radii, however, they are typically shorter and sharper than seen elsewhere. In addition, these spikes occur in "patches" and there are also clear periods within the same stream when they do not occur; the timescale of these patches might be related to the rate at which the spacecraft magnetic footpoint tracks across the coronal hole from which the plasma originated. While the velocity fluctuations associated with these spikes are typically under 100 km s-1, du. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 45 DOI: 10.3847/1538-4365/ab5b15 Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab5b15
More Details

Authors: Nisticò Giuseppe, Bothmer Volker, Vourlidas Angelos, Liewer Paulett C., Thernisien Arnaud F., et al.
Title: Simulating White-Light Images of Coronal Structures for Parker Solar Probe/WISPR: Study of the Total Brightness Profiles
Abstract:

The Wide-field Imager for Parker Solar Probe (WISPR) captures unprecedented white-light images of the solar corona and inner heliosphere. Thanks to the uniqueness of the Parker Solar Probe’s (PSP) orbit, WISPR is able to image "locally" coronal structures at high spatial and time resolutions. The observed plane of sky, however, rapidly changes because of the PSP’s high orbital speed. Therefore, the interpretation of the dynamics of the coronal structures recorded by WISPR is not straightforward. A first study, undertaken by Liewer et al. (Solar Phys.294, 93, 2019), shows how different coronal features (e.g., streamers, flux ropes) appear in the field-of-view of WISPR by means of raytracing simulations. In particular, they analyze the effects of the spatial resolution changes on both. . .
Date: 04/2020 Publisher: Solar Physics DOI: 10.1007/s11207-020-01626-y Available at: http://link.springer.com/10.1007/s11207-020-01626-yhttp
More Details

Authors: Nisticò Giuseppe, Bothmer Volker, Vourlidas Angelos, Liewer Paulett C., Thernisien Arnaud F., et al.
Title: Simulating White-Light Images of Coronal Structures for Parker Solar Probe/WISPR: Study of the Total Brightness Profiles
Abstract:

The Wide-field Imager for Parker Solar Probe (WISPR) captures unprecedented white-light images of the solar corona and inner heliosphere. Thanks to the uniqueness of the Parker Solar Probe's (PSP) orbit, WISPR is able to image "locally" coronal structures at high spatial and time resolutions. The observed plane of sky, however, rapidly changes because of the PSP's high orbital speed. Therefore, the interpretation of the dynamics of the coronal structures recorded by WISPR is not straightforward. A first study, undertaken by Liewer et al. (Solar Phys.294, 93, 2019), shows how different coronal features (e.g., streamers, flux ropes) appear in the field-of-view of WISPR by means of raytracing simulations. In particular, they analyze the effects of the spatial resolution changes on both the. . .
Date: 04/2020 Publisher: Solar Physics DOI: 10.1007/s11207-020-01626-y Available at: http://link.springer.com/10.1007/s11207-020-01626-yhttp
More Details

Authors: Hill M. E., Mitchell D. G., Allen R. C., de Nolfo G. A., Vourlidas A., et al.
Title: Small, Low-energy, Dispersive Solar Energetic Particle Events Observed by Parker Solar Probe
Abstract:

The Energetic Particle Instrument─Low Energy (EPI-Lo) experiment has detected several weak, low-energy (̃30─300 keV nucleon─1) solar energetic particle (SEP) events during its first two closest approaches to the Sun, providing a unique opportunity to explore the sources of low-energy particle acceleration. As part of the Parker Solar Probe (PSP) Integrated Science Investigation of the Sun (IS☉IS) suite, EPI-Lo was designed to investigate the physics of energetic particles; however, in the special lowest-energy "time-of-flight only" product used in this study, it also responds to solar photons in a subset of approximately sunward-looking apertures lacking special light-attenuating foils. During the first three perihelia, in a frame rotating with the Sun, PSP undergoes. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 65 DOI: 10.3847/1538-4365/ab643d Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab643
More Details

Pages