Found 407 results
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3
Authors: de Patoul Judith, Foullon Claire, and Riley Pete
Title: 3D ELECTRON DENSITY DISTRIBUTIONS IN THE SOLAR CORONA DURING SOLAR MINIMA: ASSESSMENT FOR MORE REALISTIC SOLAR WIND MODELING
Abstract:

Knowledge of the electron density distribution in the solar corona put constraints on the magnetic field configurations for coronal modeling and on initial conditions for solar wind modeling. We work with polarized SOHO/LASCO-C2 images from the last two recent minima of solar activity (1996-1997 and 2008-2010), devoid of coronal mass ejections. The goals are to derive the 4D electron density distributions in the corona by applying a newly developed time-dependent tomographic reconstruction method and to compare the results between the two solar minima and with two magnetohydrodynamic models. First, we confirm that the values of the density distribution in thermodynamic models are more realistic than in polytropic ones. The tomography provides more accurate distributions in the polar reg. . .
Date: 11/2015 Publisher: The Astrophysical Journal Pages: 68 DOI: 10.1088/0004-637X/814/1/68 Available at: http://stacks.iop.org/0004-637X/814/i=1/a=68?key=crossref.845557cfda4b2a3786588c8b62dbb093
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Authors: de Patoul Judith, Foullon Claire, and Riley Pete
Title: 3D ELECTRON DENSITY DISTRIBUTIONS IN THE SOLAR CORONA DURING SOLAR MINIMA: ASSESSMENT FOR MORE REALISTIC SOLAR WIND MODELING
Abstract:

Knowledge of the electron density distribution in the solar corona put constraints on the magnetic field configurations for coronal modeling and on initial conditions for solar wind modeling. We work with polarized SOHO/LASCO-C2 images from the last two recent minima of solar activity (1996-1997 and 2008-2010), devoid of coronal mass ejections. The goals are to derive the 4D electron density distributions in the corona by applying a newly developed time-dependent tomographic reconstruction method and to compare the results between the two solar minima and with two magnetohydrodynamic models. First, we confirm that the values of the density distribution in thermodynamic models are more realistic than in polytropic ones. The tomography provides more accurate distributions in the polar reg. . .
Date: 11/2015 Publisher: The Astrophysical Journal Pages: 68 DOI: 10.1088/0004-637X/814/1/68 Available at: http://stacks.iop.org/0004-637X/814/i=1/a=68?key=crossref.845557cfda4b2a3786588c8b62dbb093
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4
Authors: Stewart R.G., and Plus D.
Title: A 40 ns CMOS E/SUP 2/PROM
Abstract:

New high-performance CMOS circuit techniques have been developed and used to build an 8K E/SUP 2/PROM with an access time of 38 ns at 5 V. Using standard CMOS/SOS technology, the device dissipates only 0.8 mW quiescent power at 5 V and 60 mW at 1 MHz. A midpoint precharge and sense technique permits operation form a supply voltage of 4-12 V.


Date: 10/1982 Publisher: IEEE Journal of Solid-State Circuits Pages: 841 - 846 DOI: 10.1109/JSSC.1982.1051828 Available at: http://ieeexplore.ieee.org/document/1051828/http://xplorestaging.ieee.org/ielx5/4/22585/01051828.pdf?arnumber=1051828
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Authors: Kong Xiangliang, Guo Fan, Giacalone Joe, Li Hui, and Chen Yao
Title: The Acceleration of High-energy Protons at Coronal Shocks: The Effect of Large-scale Streamer-like Magnetic Field Structures
Abstract:

Recent observations have shown that coronal shocks driven by coronal mass ejections can develop and accelerate particles within several solar radii in large solar energetic particle (SEP) events. Motivated by this, we present an SEP acceleration study that including the process in which a fast shock propagates through a streamer-like magnetic field with both closed and open field lines in the low corona region. The acceleration of protons is modeled by numerically solving the Parker transport equation with spatial diffusion both along and across the magnetic field. We show that particles can be sufficiently accelerated to up to several hundred MeV within 2-3 solar radii. When the shock propagates through a streamer-like magnetic field, particles are more efficiently accelerated compared. . .
Date: 12/2017 Publisher: The Astrophysical Journal Pages: 38 DOI: 10.3847/1538-4357/aa97d7 Available at: http://stacks.iop.org/0004-637X/851/i=1/a=38?key=crossref.2009ec10fbd1f6f8cd1462070076984f
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Authors: Kong Xiangliang, Guo Fan, Giacalone Joe, Li Hui, and Chen Yao
Title: The Acceleration of High-energy Protons at Coronal Shocks: The Effect of Large-scale Streamer-like Magnetic Field Structures
Abstract:

Recent observations have shown that coronal shocks driven by coronal mass ejections can develop and accelerate particles within several solar radii in large solar energetic particle (SEP) events. Motivated by this, we present an SEP acceleration study that including the process in which a fast shock propagates through a streamer-like magnetic field with both closed and open field lines in the low corona region. The acceleration of protons is modeled by numerically solving the Parker transport equation with spatial diffusion both along and across the magnetic field. We show that particles can be sufficiently accelerated to up to several hundred MeV within 2-3 solar radii. When the shock propagates through a streamer-like magnetic field, particles are more efficiently accelerated compared. . .
Date: 12/2017 Publisher: The Astrophysical Journal Pages: 38 DOI: 10.3847/1538-4357/aa97d7 Available at: http://stacks.iop.org/0004-637X/851/i=1/a=38?key=crossref.2009ec10fbd1f6f8cd1462070076984f
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Authors: Bastian T. S.
Title: AIP Conference ProceedingsA view from the ground: Next generation instrumentation for solar and heliospheric physics
Abstract:

The solar and space physics community has recently completed its second decadal survey under the auspices of the National Research Council. An integrated strategy for ground and space based studies of the Sun and space physics has been recommended, with specific recommendations made regarding new instrumentation, programs, and facilities. The ground based component of these recommendations is briefly reviewed here: the Advanced Technology Solar Telescope (ATST), the Frequency Agile Solar Radiotelescope (FASR), and the Coronal Solar Magnetism Observatory (COSMO). Although not considered as part of the decadal portfolio, but of which the community should nevertheless be aware, are the Atacama Large Millimeter/submillimeter Array (ALMA) and the Jansky Very Large Array (VLA). Several additi. . .
Date: 07/2013 Publisher: AIP DOI: 10.1063/1.4811080 Available at: http://aip.scitation.org/doi/abs/10.1063/1.4811080
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Authors: Bastian T. S.
Title: AIP Conference ProceedingsA view from the ground: Next generation instrumentation for solar and heliospheric physics
Abstract:

The solar and space physics community has recently completed its second decadal survey under the auspices of the National Research Council. An integrated strategy for ground and space based studies of the Sun and space physics has been recommended, with specific recommendations made regarding new instrumentation, programs, and facilities. The ground based component of these recommendations is briefly reviewed here: the Advanced Technology Solar Telescope (ATST), the Frequency Agile Solar Radiotelescope (FASR), and the Coronal Solar Magnetism Observatory (COSMO). Although not considered as part of the decadal portfolio, but of which the community should nevertheless be aware, are the Atacama Large Millimeter/submillimeter Array (ALMA) and the Jansky Very Large Array (VLA). Several additi. . .
Date: 07/2013 Publisher: AIP DOI: 10.1063/1.4811080 Available at: http://aip.scitation.org/doi/abs/10.1063/1.4811080
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Authors: Case A. W., Kasper J. C., Daigneau P. S., Caldwell D., Freeman M., et al.
Title: AIP Conference ProceedingsDesigning a sun-pointing Faraday cup for solar probe plus
Abstract:

The NASA Solar Probe Plus (SPP) mission will be the first spacecraft to pass through the sub-Alfvénic solar corona. The objectives of the mission are to trace the flow of energy that heats and accelerates the solar corona and solar wind, to determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind, and to explore mechanisms that accelerate and transport energetic particles. The Solar Wind Electrons, Alphas, and Protons (SWEAP) Investigation instrument suite on SPP will measure the bulk solar wind conditions in the inner heliosphere. SWEAP consists of the Solar Probe Cup (SPC), a sun-pointing Faraday Cup, and the Solar Probe ANalyzers (SPAN), a set of 3 electrostatic analyzers that will reside in the penumbra of SPP's thermal protection syst. . .
Date: Publisher: AIP DOI: 10.1063/1.4811083 Available at: http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.4811083
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Authors: Case A. W., Kasper J. C., Daigneau P. S., Caldwell D., Freeman M., et al.
Title: AIP Conference ProceedingsDesigning a sun-pointing Faraday cup for solar probe plus
Abstract:

The NASA Solar Probe Plus (SPP) mission will be the first spacecraft to pass through the sub-Alfvénic solar corona. The objectives of the mission are to trace the flow of energy that heats and accelerates the solar corona and solar wind, to determine the structure and dynamics of the plasma and magnetic fields at the sources of the solar wind, and to explore mechanisms that accelerate and transport energetic particles. The Solar Wind Electrons, Alphas, and Protons (SWEAP) Investigation instrument suite on SPP will measure the bulk solar wind conditions in the inner heliosphere. SWEAP consists of the Solar Probe Cup (SPC), a sun-pointing Faraday Cup, and the Solar Probe ANalyzers (SPAN), a set of 3 electrostatic analyzers that will reside in the penumbra of SPP’s thermal protection sy. . .
Date: Publisher: AIP DOI: 10.1063/1.4811083 Available at: http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.4811083
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Authors: Wicks Robert T., Matteini Lorenzo, Horbury Timothy S., Hellinger Petr, and Roberts Aaron
Title: AIP Conference ProceedingsTemperature anisotropy instabilities; combining plasma and magnetic field data at different distances from the Sun
Abstract:

We present a new data analysis method enabling the observation of magnetic field fluctuations associated with temperature anisotropy instabilities using the Ulysses spacecraft. The movement of the spacecraft away from the Sun causes the observed plasma conditions, turbulent fluctuation amplitude, magnetic field strength and important physical scales to change. We normalize wavelet power spectra of the magnetic field using local values for the proton gyroscale and large scale magnetic field fluctuation amplitude to remove the effects of varying heliocentric distance. We recover the enhancement of magnetic fluctuations where temperature anisotropy instability growth rates are large, as seen by previous studies in the ecliptic at 1 AU. This method can be applied to any spacecraft data that. . .
Date: 07/2013 Publisher: AIP DOI: 10.1063/1.4811048 Available at: http://aip.scitation.org/doi/abs/10.1063/1.4811048
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Authors: Wicks Robert T., Matteini Lorenzo, Horbury Timothy S., Hellinger Petr, and Roberts Aaron
Title: AIP Conference ProceedingsTemperature anisotropy instabilities; combining plasma and magnetic field data at different distances from the Sun
Abstract:

We present a new data analysis method enabling the observation of magnetic field fluctuations associated with temperature anisotropy instabilities using the Ulysses spacecraft. The movement of the spacecraft away from the Sun causes the observed plasma conditions, turbulent fluctuation amplitude, magnetic field strength and important physical scales to change. We normalize wavelet power spectra of the magnetic field using local values for the proton gyroscale and large scale magnetic field fluctuation amplitude to remove the effects of varying heliocentric distance. We recover the enhancement of magnetic fluctuations where temperature anisotropy instability growth rates are large, as seen by previous studies in the ecliptic at 1 AU. This method can be applied to any spacecraft data that. . .
Date: 07/2013 Publisher: AIP DOI: 10.1063/1.4811048 Available at: http://aip.scitation.org/doi/abs/10.1063/1.4811048
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Authors: Goelzer Molly L., Schwadron Nathan A., and Smith Charles W.
Title: An analysis of Alfvén radius based on sunspot number from 1749 to today
Abstract:

The Solar Probe Plus mission now under construction will provide the first in situ measurements from inside the orbit of Mercury. The most critical part of that mission will be measurements from inside the Alfvén radius where the Alfvén speed exceeds the wind speed and the physics of the solar wind changes fundamentally due, in part, to the multidirectionality of wave propagation. In this region waves from both sunward and antisunward of the observation point can effect the local dynamics including the turbulent evolution, heating, and acceleration of the plasma. While the location of this point can change with solar wind conditions, we ask the question of whether there is a systematic dependence on the solar cycle that moves the average Alfvén radius to different locations depending. . .
Date: 01/2014 Publisher: Journal of Geophysical Research: Space Physics Pages: 115 - 120 DOI: 10.1002/2013JA019420 Available at: http://doi.wiley.com/10.1002/2013JA019420http://onlinelibrary.wiley.com/wol1/doi/10.1002/2013JA019420/fullpdf
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Authors: Goelzer Molly L., Schwadron Nathan A., and Smith Charles W.
Title: An analysis of Alfvén radius based on sunspot number from 1749 to today
Abstract:

The Solar Probe Plus mission now under construction will provide the first in situ measurements from inside the orbit of Mercury. The most critical part of that mission will be measurements from inside the Alfvén radius where the Alfvén speed exceeds the wind speed and the physics of the solar wind changes fundamentally due, in part, to the multidirectionality of wave propagation. In this region waves from both sunward and antisunward of the observation point can effect the local dynamics including the turbulent evolution, heating, and acceleration of the plasma. While the location of this point can change with solar wind conditions, we ask the question of whether there is a systematic dependence on the solar cycle that moves the average Alfvén radius to different locations depending. . .
Date: 01/2014 Publisher: Journal of Geophysical Research: Space Physics Pages: 115 - 120 DOI: 10.1002/2013JA019420 Available at: http://doi.wiley.com/10.1002/2013JA019420http://onlinelibrary.wiley.com/wol1/doi/10.1002/2013JA019420/fullpdf
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Authors: Nieves-Chinchilla Teresa, Szabo Adam, Korreck Kelly E., Alzate Nathalia, Balmaceda Laura A., et al.
Title: Analysis of the Internal Structure of the Streamer Blowout Observed by the Parker Solar Probe During the First Solar Encounter
Abstract:

In this paper, we present an analysis of the internal structure of a coronal mass ejection (CME) detected by in situ instruments on board the Parker Solar Probe (PSP) spacecraft during its first solar encounter. On 2018 November 11 at 23:53 UT, the FIELDS magnetometer measured an increase in strength of the magnetic field as well as a coherent change in the field direction. The SWEAP instrument simultaneously detected a low proton temperature and signatures of bidirectionality in the electron pitch angle distribution (PAD). These signatures are indicative of a CME embedded in the slow solar wind. Operating in conjunction with PSP was the STEREO A spacecraft, which enabled the remote observation of a streamer blowout by the SECCHI suite of instruments. The source at the Sun of the slow a. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 63 DOI: 10.3847/1538-4365/ab61f5 Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab61f5
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Authors: Nieves-Chinchilla Teresa, Szabo Adam, Korreck Kelly E., Alzate Nathalia, Balmaceda Laura A., et al.
Title: Analysis of the Internal Structure of the Streamer Blowout Observed by the Parker Solar Probe During the First Solar Encounter
Abstract:

In this paper, we present an analysis of the internal structure of a coronal mass ejection (CME) detected by in situ instruments on board the Parker Solar Probe (PSP) spacecraft during its first solar encounter. On 2018 November 11 at 23:53 UT, the FIELDS magnetometer measured an increase in strength of the magnetic field as well as a coherent change in the field direction. The SWEAP instrument simultaneously detected a low proton temperature and signatures of bidirectionality in the electron pitch angle distribution (PAD). These signatures are indicative of a CME embedded in the slow solar wind. Operating in conjunction with PSP was the STEREO A spacecraft, which enabled the remote observation of a streamer blowout by the SECCHI suite of instruments. The source at the Sun of the slow a. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 63 DOI: 10.3847/1538-4365/ab61f5 Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab61f5
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Authors: Maksimovic M., Bale S. D., Berčič L., Bonnell J. W., Case A. W., et al.
Title: Anticorrelation between the Bulk Speed and the Electron Temperature in the Pristine Solar Wind: First Results from the Parker Solar Probe and Comparison with Helios
Abstract:

We discuss the solar wind electron temperatures Te as measured in the nascent solar wind by Parker Solar Probe during its first perihelion pass. The measurements have been obtained by fitting the high-frequency part of quasi-thermal noise spectra recorded by the Radio Frequency Spectrometer. In addition we compare these measurements with those obtained by the electrostatic analyzer discussed in Halekas et al. These first electron observations show an anticorrelation between Te and the wind bulk speed V: this anticorrelation is most likely the remnant of the well-known mapping observed at 1 au and beyond between the fast wind and its coronal hole sources, where electrons are observed to be cooler than in the quiet corona. We also revisit Helios electron temperature . . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 62 DOI: 10.3847/1538-4365/ab61fc Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab61fch
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Authors: Maksimovic M., Bale S. D., Berčič L., Bonnell J. W., Case A. W., et al.
Title: Anticorrelation between the Bulk Speed and the Electron Temperature in the Pristine Solar Wind: First Results from the Parker Solar Probe and Comparison with Helios
Abstract:

We discuss the solar wind electron temperatures Te as measured in the nascent solar wind by Parker Solar Probe during its first perihelion pass. The measurements have been obtained by fitting the high-frequency part of quasi-thermal noise spectra recorded by the Radio Frequency Spectrometer. In addition we compare these measurements with those obtained by the electrostatic analyzer discussed in Halekas et al. These first electron observations show an anticorrelation between Te and the wind bulk speed V: this anticorrelation is most likely the remnant of the well-known mapping observed at 1 au and beyond between the fast wind and its coronal hole sources, where electrons are observed to be cooler than in the quiet corona. We also revisit Helios electron temperature . . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 62 DOI: 10.3847/1538-4365/ab61fc Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab61fch
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Authors: Park Il Heung, Lee Hyun Su, Oh Suyeon, Kwak Young-Sil, Wiedenbeck M. E., et al.
Title: Capabilities and Performance of the High-Energy Energetic-Particles Instrument for the Parker Solar Probe Mission
Abstract:

NASA’s Parker Solar Probe (PSP) spacecraft (formerly Solar Probe Plus) is scheduled for launch in July 2018 with a planned heliocentric orbit that will carry it on a series of close passes by the Sun with perihelion distances that eventually will get below 10 solar radii. Among other in-situ and imaging sensors, the PSP payload includes the two-instrument “Integrated Science Investigation of the Sun” suite, which will make coordinated measurements of energetic ions and electrons. The high-energy instrument (EPI-Hi), operating in the MeV energy range, consists of three detector-telescopes using silicon solid-state sensors for measuring composition, energy spectra, angular distributions, and time structure in solar energetic particle events. The expected performance of this instrume. . .
Date: 10/2017 Publisher: Sissa Medialab DOI: 10.22323/1.301.0016 Available at: https://pos.sissa.it/301/016
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Authors: Wiedenbeck M. E., Angold N. G., Birdwell B., Burnham J. A., Christian E. R., et al.
Title: Capabilities and Performance of the High-Energy Energetic-Particles Instrument for the Parker Solar Probe Mission
Abstract:

NASA’s Parker Solar Probe (PSP) spacecraft (formerly Solar Probe Plus) is scheduled for launch in July 2018 with a planned heliocentric orbit that will carry it on a series of close passes by the Sun with perihelion distances that eventually will get below 10 solar radii. Among other in-situ and imaging sensors, the PSP payload includes the two-instrument “Integrated Science Investigation of the Sun” suite, which will make coordinated measurements of energetic ions and electrons. The high-energy instrument (EPI-Hi), operating in the MeV energy range, consists of three detector-telescopes using silicon solid-state sensors for measuring composition, energy spectra, angular distributions, and time structure in solar energetic particle events. The expected performance of this instrume. . .
Date: 10/2017 Publisher: Sissa Medialab DOI: 10.22323/1.301.0016 Available at: https://pos.sissa.it/301/016
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Authors: Daloz Anne S., Camargo S. J., Kossin J. P., Emanuel K., Horn M., et al.
Title: Cluster Analysis of Downscaled and Explicitly Simulated North Atlantic Tropical Cyclone Tracks
Abstract:

A realistic representation of the North Atlantic tropical cyclone tracks is crucial as it allows, for example, explaining potential changes in U.S. landfalling systems. Here, the authors present a tentative study that examines the ability of recent climate models to represent North Atlantic tropical cyclone tracks. Tracks from two types of climate models are evaluated: explicit tracks are obtained from tropical cyclones simulated in regional or global climate models with moderate to high horizontal resolution (1°–0.25°), and downscaled tracks are obtained using a downscaling technique with large-scale environmental fields from a subset of these models. For both configurations, tracks are objectively separated into four groups using a cluster technique, leading to a zonal and a merid. . .
Date: 02/2015 Publisher: Journal of Climate Pages: 1333 - 1361 DOI: 10.1175/JCLI-D-13-00646.1 Available at: http://journals.ametsoc.org/doi/10.1175/JCLI-D-13-00646.1
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Authors: Chhiber Rohit, Goldstein M L., Maruca B. A., Chasapis A., Matthaeus W. H., et al.
Title: Clustering of Intermittent Magnetic and Flow Structures near Parker Solar Probe ’s First Perihelion—A Partial-variance-of-increments Analysis
Abstract:

During the Parker Solar Probe’s (PSP) first perihelion pass, the spacecraft reached within a heliocentric distance of ̃37 R and observed numerous magnetic and flow structures characterized by sharp gradients. To better understand these intermittent structures in the young solar wind, an important property to examine is their degree of correlation in time and space. To this end, we use the well-tested partial variance of increments (PVI) technique to identify intermittent events in FIELDS and SWEAP observations of magnetic and proton-velocity fields (respectively) during PSP’s first solar encounter, when the spacecraft was within 0.25 au from the Sun. We then examine distributions of waiting times (WT) between events with varying separation and PVI thresholds. We find . . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 31 DOI: 10.3847/1538-4365/ab53d2 Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab53d2
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Authors: Chhiber Rohit, Goldstein M L., Maruca B. A., Chasapis A., Matthaeus W. H., et al.
Title: Clustering of Intermittent Magnetic and Flow Structures near Parker Solar Probe ’s First Perihelion—A Partial-variance-of-increments Analysis
Abstract:

During the Parker Solar Probe's (PSP) first perihelion pass, the spacecraft reached within a heliocentric distance of ̃37 R and observed numerous magnetic and flow structures characterized by sharp gradients. To better understand these intermittent structures in the young solar wind, an important property to examine is their degree of correlation in time and space. To this end, we use the well-tested partial variance of increments (PVI) technique to identify intermittent events in FIELDS and SWEAP observations of magnetic and proton-velocity fields (respectively) during PSP's first solar encounter, when the spacecraft was within 0.25 au from the Sun. We then examine distributions of waiting times (WT) between events with varying separation and PVI thresholds. We find powe. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 31 DOI: 10.3847/1538-4365/ab53d2 Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab53d2
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Authors: Bowen Trevor A., Mallet Alfred, Bale Stuart D., Bonnell J. W., Case Anthony W., et al.
Title: Constraining Ion-Scale Heating and Spectral Energy Transfer in Observations of Plasma Turbulence
Abstract:

We perform a statistical study of the turbulent power spectrum at inertial and kinetic scales observed during the first perihelion encounter of the Parker Solar Probe. We find that often there is an extremely steep scaling range of the power spectrum just above the ion-kinetic scales, similar to prior observations at 1 A.U., with a power-law index of around -4 . Based on our measurements, we demonstrate that either a significant (>50 %) fraction of the total turbulent energy flux is dissipated in this range of scales, or the characteristic nonlinear interaction time of the turbulence decreases dramatically from the expectation based solely on the dispersive nature of nonlinearly interacting kinetic Alfvén waves.


Date: 07/2020 Publisher: Physical Review Letters DOI: 10.1103/PhysRevLett.125.025102 Available at: https://link.aps.org/doi/10.1103/PhysRevLett.125.025102http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.125.025102/fulltexthttps://link.aps.org/article/10.1103/PhysRevLett.125.025102
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Authors: Bowen Trevor A., Mallet Alfred, Bale Stuart D., Bonnell J. W., Case Anthony W., et al.
Title: Constraining Ion-Scale Heating and Spectral Energy Transfer in Observations of Plasma Turbulence
Abstract:

We perform a statistical study of the turbulent power spectrum at inertial and kinetic scales observed during the first perihelion encounter of the Parker Solar Probe. We find that often there is an extremely steep scaling range of the power spectrum just above the ion-kinetic scales, similar to prior observations at 1 A.U., with a power-law index of around -4 . Based on our measurements, we demonstrate that either a significant (>50 %) fraction of the total turbulent energy flux is dissipated in this range of scales, or the characteristic nonlinear interaction time of the turbulence decreases dramatically from the expectation based solely on the dispersive nature of nonlinearly interacting kinetic Alfvén waves.


Date: 07/2020 Publisher: Physical Review Letters DOI: 10.1103/PhysRevLett.125.025102 Available at: https://link.aps.org/doi/10.1103/PhysRevLett.125.025102http://harvest.aps.org/v2/journals/articles/10.1103/PhysRevLett.125.025102/fulltexthttps://link.aps.org/article/10.1103/PhysRevLett.125.025102
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Authors: Tracy Patrick J., Kasper Justin C., Raines Jim M., Shearer Paul, Gilbert Jason A., et al.
Title: Constraining Solar Wind Heating Processes by Kinetic Properties of Heavy Ions
Abstract:

We analyze the heavy ion components (A >4 amu ) in collisionally young solar wind plasma and show that there is a clear, stable dependence of temperature on mass, probably reflecting the conditions in the solar corona. We consider both linear and power law forms for the dependence and find that a simple linear fit of the form Ti/Tp=(1.35 ±.02 )mi/mp describes the observations twice as well as the equivalent best fit power law of the form Ti/Tp=(mi/mp) 1.07 ±.01 . Most importantly we find that current model predictions based on turbulent transport and kinetic dissipation are in agreement with observed nonthermal heating in intermediate collisional age plasma for m /q <3.5 , but are . . .
Date: 06/2016 Publisher: Physical Review Letters DOI: 10.1103/PhysRevLett.116.255101 Available at: https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.255101
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