Found 6 results
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2020
Authors: Cohen C. M. S., Christian E. R., Cummings A. C., Davis A. J., Desai M. I., et al.
Title: Energetic Particle Increases Associated with Stream Interaction Regions
Abstract:

The Parker Solar Probe was launched on 2018 August 12 and completed its second orbit on 2019 June 19 with perihelion of 35.7 solar radii. During this time, the Energetic Particle Instrument-Hi (EPI-Hi, one of the two energetic particle instruments comprising the Integrated Science Investigation of the Sun, IS☉IS) measured seven proton intensity increases associated with stream interaction regions (SIRs), two of which appear to be occurring in the same region corotating with the Sun. The events are relatively weak, with observed proton spectra extending to only a few MeV and lasting for a few days. The proton spectra are best characterized by power laws with indices ranging from −4.3 to −6.5, generally softer than events associated with SIRs observed at 1 au and beyond. Helium spec. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 20 DOI: 10.3847/1538-4365/ab4c38 Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab4c38
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Authors: Allen R. C., Lario D., Odstrcil D., Ho G. C., Jian L. K., et al.
Title: Solar Wind Streams and Stream Interaction Regions Observed by the Parker Solar Probe with Corresponding Observations at 1 au
Abstract:

Several fast solar wind streams and stream interaction regions (SIRs) were observed by the Parker Solar Probe (PSP) during its first orbit (2018 September─2019 January). During this time, several recurring SIRs were also seen at 1 au at both L1 (Advanced Composition Explorer (ACE) and Wind) and the location of the Solar Terrestrial Relations Observatory-Ahead (STEREO-A). In this paper, we compare four fast streams observed by PSP at different radial distances during its first orbit. For three of these fast stream events, measurements from L1 (ACE and Wind) and STEREO-A indicated that the fast streams were observed by both PSP and at least one of the 1 au monitors. Our associations are supported by simulations made by the ENLIL model driven by GONG-(ADAPT-)WSA, which allows us to conte. . .
Date: 02/2020 Publisher: The Astrophysical Journal Supplement Series Pages: 36 DOI: 10.3847/1538-4365/ab578f Available at: https://iopscience.iop.org/article/10.3847/1538-4365/ab578f
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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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2016
Authors: Fox N. J., Velli M. C., Bale S. D., Decker R., Driesman A., et al.
Title: The Solar Probe Plus Mission: Humanity’s First Visit to Our Star
Abstract:

Solar Probe Plus (SPP) will be the first spacecraft to fly into the low solar corona. SPP's main science goal is to determine the structure and dynamics of the Sun's coronal magnetic field, understand how the solar corona and wind are heated and accelerated, and determine what processes accelerate energetic particles. Understanding these fundamental phenomena has been a top-priority science goal for over five decades, dating back to the 1958 Simpson Committee Report. The scale and concept of such a mission has been revised at intervals since that time, yet the core has always been a close encounter with the Sun. The mission design and the technology and engineering developments enable SPP to meet its science objectives to: (1) Trace the flow of energy that heats and accelerates the sola. . .
Date: 12/2016 Publisher: Space Science Reviews Pages: 7 - 48 DOI: 10.1007/s11214-015-0211-6 Available at: http://link.springer.com/10.1007/s11214-015-0211-6http://link.springer.com/content/pdf/10.1007/s11214-015-0211-6.pdf
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2012
Authors: Lario D.
Title: Estimation of the solar flare neutron worst-case fluxes and fluences for missions traveling close to the Sun
Abstract:

A method to estimate the total fluence of solar flare neutrons at a spacecraft traveling in the innermost part of the heliosphere (at heliocentric radial distances of <1 AU) is presented. The results of the neutron production and emissivity codes of Hua and Lingenfelter (1987a, 1987b) scaled to one of the largest solar neutron events ever observed at the Earth are used to derive a conservative estimate of the energy spectrum of neutrons emitted from the Sun after a large solar flare. By taking into account the survival probability of a neutron to reach a certain heliocentric distance, we evaluate the observed time-integrated spectrum of solar neutrons as a function of the heliocentric distance of the observer. By considering (1) a working relationship between the soft X-ray class of . . .
Date: 03/2012 Publisher: Space Weather Pages: n/a - n/a DOI: 10.1029/2011SW000732 Available at: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011SW000732
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2011
Authors: Lario D., and Decker R. B.
Title: Estimation of solar energetic proton mission-integrated fluences and peak intensities for missions traveling close to the Sun
Abstract:

A method to estimate both solar energetic particle mission-integrated fluences and solar energetic particle peak intensities for missions traveling through the innermost part of the heliosphere (r < 1 AU) is presented. By using (1) an extensive data set of particle intensities measured at 1 AU over the last three solar cycles, (2) successive launch dates for the mission traveling close to the Sun over the time interval spanned by our data set, and (3) appropriate radial dependences to extrapolate fluences and peak intensities measured at 1 AU to the heliocentric radial distance of the mission at each specific time, we generate distributions of both mission-integrated fluences and maximum peak intensities. From these distributions we extract the values of mission-integrated fluence an. . .
Date: 11/2011 Publisher: Space Weather Pages: n/a - n/a DOI: 10.1029/2011SW000708 Available at: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011SW000708
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