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Found 20 entries in the Bibliography.
Showing entries from 1 through 20
| 2022 |
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The Dynamic Structure of Coronal Hole Boundaries The boundaries of solar coronal holes are difficult to uniquely define observationally but are sites of interest in part because the slow solar wind appears to originate there. The aim of this article is to explore the dynamics of interchange magnetic reconnection at different types of coronal hole boundaries- namely streamers and pseudostreamers-and their implications for the coronal structure. We describe synthetic observables derived from three-dimensional magnetohydrodynamic simulations of the atmosphere of the Sun in wh ... Aslanyan, V.; Pontin, D.~I.; Scott, R.~B.; Higginson, A.~K.; Wyper, P.~F.; Antiochos, S.~K.; Published by: \apj Published on: jun YEAR: 2022 DOI: 10.3847/1538-4357/ac69ed Parker Data Used; Solar Physics; Solar magnetic reconnection; Solar corona; Solar coronal holes; Slow solar wind; Magnetohydrodynamics; 1476; 1504; 1483; 1484; 1873; 1964 |
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Constraining Global Coronal Models with Multiple Independent Observables Global coronal models seek to produce an accurate physical representation of the Sun s atmosphere that can be used, for example, to drive space-weather models. Assessing their accuracy is a complex task, and there are multiple observational pathways to provide constraints and tune model parameters. Here, we combine several such independent constraints, defining a model- agnostic framework for standardized comparison. We require models to predict the distribution of coronal holes at the photosphere, and neutral line topology ... Badman, Samuel; Brooks, David; Poirier, Nicolas; Warren, Harry; Petrie, Gordon; Rouillard, Alexis; Arge, Nick; Bale, Stuart; Agüero, Diego; Harra, Louise; Jones, Shaela; Kouloumvakos, Athanasios; Riley, Pete; Panasenco, Olga; Velli, Marco; Wallace, Samantha; Published by: \apj Published on: jun YEAR: 2022 DOI: 10.3847/1538-4357/ac6610 Parker Data Used; Solar Physics; Solar corona; Solar coronal holes; Astronomical models; 1476; 1483; 1484; 86; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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We report the result of the first search for multipoint in situ and imaging observations of interplanetary coronal mass ejections (ICMEs) starting with the first Solar Orbiter (SolO) data in 2020 April-2021 April. A data exploration analysis is performed including visualizations of the magnetic-field and plasma observations made by the five spacecraft SolO, BepiColombo, Parker Solar Probe (PSP), Wind, and STEREO-A, in connection with coronagraph and heliospheric imaging observations from STEREO-A/SECCHI and SOHO/LASCO. We id ... Möstl, Christian; Weiss, Andreas; Reiss, Martin; Amerstorfer, Tanja; Bailey, Rachel; Hinterreiter, Jürgen; Bauer, Maike; Barnes, David; Davies, Jackie; Harrison, Richard; von Forstner, Johan; Davies, Emma; Heyner, Daniel; Horbury, Tim; Bale, Stuart; Published by: \apjl Published on: jan YEAR: 2022 DOI: 10.3847/2041-8213/ac42d0 Parker Data Used; 310; 1526; 1534; 1476; 827; 824; 829; 711; 2037; 1472; 1528; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Anomalous Cosmic-Ray Oxygen Observations into 0.1 au The Integrated Science Investigation of the Sun instrument suite onboard NASA s Parker Solar Probe mission continues to measure solar energetic particles and cosmic rays closer to the Sun than ever before. Here, we present the first observations of cosmic rays into 0.1 au (21.5 solar radii), focusing specifically on oxygen from \raisebox-0.5ex\textasciitilde2018.7 to \raisebox-0.5ex\textasciitilde2021.2. Our energy spectra reveal an anomalous cosmic-ray-dominated profile that is comparable to that at 1 au, across multiple so ... Rankin, J.~S.; McComas, D.~J.; Leske, R.~A.; Christian, E.~R.; Cohen, C.~M.~S.; Cummings, A.~C.; Joyce, C.~J.; Labrador, A.~W.; Mewaldt, R.~A.; Schwadron, N.~A.; Stone, E.~C.; Strauss, R.~D.; Wiedenbeck, M.~E.; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac348f Parker Data Used; 567; 329; 1487; 1193; 1503; 1476; 1534; 96; 1544; 711; 1322; 830; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Alpha-Proton Differential Flow of the Young Solar Wind: Parker Solar Probe Observations The velocity of alpha particles relative to protons can vary depending on the solar wind type and distance from the Sun. Measurements from the previous spacecraft provided the alpha-proton differential velocities down to 0.3 au. The Parker Solar Probe (PSP) now enables insights into differential flows of the newly accelerated solar wind closer to the Sun for the first time. Here we study the difference between proton and alpha bulk velocities near PSP perihelia of encounters 3-7 when the core solar wind is in the field of vi ... Mostafavi, P.; Allen, R.~C.; McManus, M.~D.; Ho, G.~C.; Raouafi, N.~E.; Larson, D.~E.; Kasper, J.~C.; Bale, S.~D.; Published by: \apjl Published on: feb YEAR: 2022 DOI: 10.3847/2041-8213/ac51e1 Parker Data Used; 1534; 1544; 1492; 1476; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics |
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Turbulence in the Sub-Alfv\ enic Solar Wind The Parker Solar Probe (PSP) entered a region of sub-Alfv\ enic solar wind during encounter 8, and we present the first detailed analysis of low-frequency turbulence properties in this novel region. The magnetic field and flow velocity vectors were highly aligned during this interval. By constructing spectrograms of the normalized magnetic helicity, cross-helicity, and residual energy, we find that PSP observed primarily Alfv\ enic fluctuations, a consequence of the highly field-aligned flow that renders quasi-2D fluctuation ... Zank, G.~P.; Zhao, L.; Adhikari, L.; Telloni, D.; Kasper, J.~C.; Stevens, M.; Rahmati, A.; Bale, S.~D.; Published by: \apjl Published on: feb YEAR: 2022 DOI: 10.3847/2041-8213/ac51da |
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An Improved Technique for Measuring Plasma Density to High Frequencies on the Parker Solar Probe The correlation between the plasma density measured in space and the surface potential of an electrically conducting satellite body with biased electric field detectors has been recognized and used to provide density proxies. However, for Parker Solar Probe, this correlation has not produced quantitative density estimates over extended periods of time because it depends on the energy-dependent exponential variation of the photoemission spectrum, the electron temperature, the ratio of the biased surface area to the conducting ... Mozer, F.~S.; Bale, S.~D.; Kellogg, P.~J.; Larson, D.; Livi, R.; Romeo, O.; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac4f42 Parker Data Used; 1534; 1476; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics |
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Parker Solar Probe (PSP) and SolO data are utilized to investigate magnetic field intermittency in the solar wind (SW). Small-scale intermittency (20-100 d $_ i $) is observed to radially strengthen when methods relying on higher-order moments are considered (SF$_ q $; SDK), but no clear trend is observed at larger scales. However, lower-order moment-based methods (e.g., partial variance of increments; PVI) are deemed more appropriate for examining the evolution of the bulk of coherent structures (CSs), PVI \ensuremath\geq 3 ... Sioulas, Nikos; Huang, Zesen; Velli, Marco; Chhiber, Rohit; Cuesta, Manuel; Shi, Chen; Matthaeus, William; Bandyopadhyay, Riddhi; Vlahos, Loukas; Bowen, Trevor; Qudsi, Ramiz; Bale, Stuart; Owen, Christopher; Louarn, P.; Fedorov, A.; c, Milan; Stevens, Michael; Case, Anthony; Kasper, Justin; Larson, Davin; Pulupa, Marc; Livi, Roberto; Published by: \apj Published on: aug YEAR: 2022 DOI: 10.3847/1538-4357/ac7aa2 Parker Data Used; Solar wind; interplanetary turbulence; Magnetohydrodynamics; Space plasmas; Plasma astrophysics; Solar Physics; 1534; 830; 1964; 1544; 1261; 1476; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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The Dynamic Coupling of Streamers and Pseudostreamers to the Heliosphere The slow solar wind is generally believed to result from the interaction of open and closed coronal magnetic flux at streamers and pseudostreamers. We use three-dimensional magnetohydrodynamic simulations to determine the detailed structure and dynamics of open-closed interactions that are driven by photospheric convective flows. The photospheric magnetic field model includes a global dipole giving rise to a streamer together with a large parasitic polarity region giving rise to a pseudostreamer that separates a satellite co ... Aslanyan, V.; Pontin, D.~I.; Higginson, A.~K.; Wyper, P.~F.; Scott, R.~B.; Antiochos, S.~K.; Published by: \apj Published on: apr YEAR: 2022 DOI: 10.3847/1538-4357/ac5d5b Parker Data Used; Solar Physics; Solar magnetic reconnection; Solar corona; Solar coronal holes; Magnetohydrodynamics; Slow solar wind; 1476; 1504; 1483; 1484; 1964; 1873; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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The physical properties responsible for the formation and evolution of the corona and heliosphere are still not completely understood. 3D MHD global modeling is a powerful tool to investigate all the possible candidate processes. To fully understand the role of each of them, we need a validation process where the output from the simulations is quantitatively compared to the observational data. In this work, we present the results from our validation process applied to the wave turbulence driven 3D MHD corona-wind model WindP ... Parenti, Susanna; eville, Victor; Brun, Allan; Pinto, Rui; Auchère, Fr\; Buchlin, Eric; Perri, Barbara; Strugarek, Antoine; Published by: \apj Published on: apr YEAR: 2022 DOI: 10.3847/1538-4357/ac56da Parker Data Used; Magnetohydrodynamical simulations; Solar Physics; Solar coronal heating; Solar coronal streamers; Solar corona; Solar extreme ultraviolet emission; Solar radiation; Solar atmosphere; 1966; 1476; 1989; 1486; 1483; 1493; 1521; 1477; Astrophysics - Solar and Stellar Astrophysics |
| 2021 |
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Parker Solar Probe (PSP) data recorded within a heliocentric radial distance of 0.3 au have revealed a magnetic field dominated by Alfv\ enic structures that undergo large local variations or even reversals of the radial magnetic field. They are called magnetic switchbacks, they are consistent with folds in magnetic field lines within a same magnetic sector and are associated with velocity spikes during an otherwise calmer background. They are thought to originate either in the low solar atmosphere through magnetic reconnect ... Fargette, Na; Lavraud, Benoit; Rouillard, Alexis; eville, Victor; de Wit, Thierry; Froment, Clara; Halekas, Jasper; Phan, Tai; Malaspina, David; Bale, Stuart; Kasper, Justin; Louarn, Philippe; Case, Anthony; Korreck, Kelly; Larson, Davin; Pulupa, Marc; Stevens, Michael; Whittlesey, Phyllis; Berthomier, Matthieu; Published by: \apj Published on: oct YEAR: 2021 DOI: 10.3847/1538-4357/ac1112 Solar wind; Solar Physics; Wavelet analysis; Supergranulation; Solar granulation; Solar magnetic fields; 1534; 1476; 1918; 1662; 1498; 1503; Astrophysics - Solar and Stellar Astrophysics; Parker Data Used |
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Switchback Boundary Dissipation and Relative Age We examine Parker Solar Probe (PSP) magnetic field and plasma observations during its first encounter with the Sun in early 2018 November. During this perihelion time, impulsive reversals in the magnetic field, called switchbacks, were found in the data set characterized by a quick rotation in B along with a simultaneous increase in solar wind flow. In this work, we examine the structure and morphology of 920 switchback boundaries as PSP enters and exits the structures, specifically looking for evidence of boundary degra ... Farrell, W.~M.; Rasca, A.~P.; MacDowall, R.~J.; Gruesbeck, J.~R.; Bale, S.~D.; Kasper, J.~C.; Published by: \apj Published on: jul YEAR: 2021 DOI: 10.3847/1538-4357/ac005b Parker Data Used; Solar wind; Solar Physics; Solar magnetic flux emergence; Solar magnetic fields; 1534; 1476; 2000; 1503 |
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Various forms of exact laws governing magnetohydrodynamic (MHD) turbulence have been derived either in the incompressibility limit, or for isothermal compressible flows. Here we propose a more general method that allows us to obtain such laws for any turbulent isentropic flow (i.e., constant entropy). We demonstrate that the known MHD exact laws (incompressible and isothermal) and the new (polytropic) one can be obtained as specific cases of the general law when the corresponding closure equation is stated. We also recover a ... Published by: \apj Published on: jul YEAR: 2021 DOI: 10.3847/1538-4357/ac0337 Solar wind; Solar Physics; Parker Data Used; Magnetohydrodynamics; Plasma astrophysics; Plasma physics; interplanetary turbulence; 1534; 1476; 1964; 1261; 2089; 830; Physics - Plasma Physics; Physics - Fluid Dynamics |
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The Formation and Lifetime of Outflows in a Solar Active Region Active regions are thought to be one contributor to the slow solar wind. Upflows in EUV coronal spectral lines are routinely observed at their boundaries, and provide the most direct way for upflowing material to escape into the heliosphere. The mechanisms that form and drive these upflows, however, remain to be fully characterized. It is unclear how quickly they form, or how long they exist during their lifetimes. They could be initiated low in the atmosphere during magnetic flux emergence, or as a response to processes occ ... Brooks, David; Harra, Louise; Bale, Stuart; Barczynski, Krzysztof; Mandrini, Cristina; Polito, Vanessa; Warren, Harry; Published by: \apj Published on: aug YEAR: 2021 DOI: 10.3847/1538-4357/ac0917 Solar Physics; Slow solar wind; Solar active regions; Solar energetic particles; 1476; 1873; 1974; 1491; Astrophysics - Solar and Stellar Astrophysics; Parker Data Used |
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Near-Sun Switchback Boundaries: Dissipation with Solar Distance The most surprising result from the first solar encounters by the Parker Solar Probe (PSP) is the large amount of brief magnetic field reversals often referred to as switchbacks. Switchbacks have previously been observed further downstream in the solar wind by spacecraft such as Helios 2 at 62 R$_s$ from the Sun. However, these observations lack a distinct proton temperature increase detected inside switchbacks by PSP, implying that they are evolving over time to eventually reach a pressure balance at the switchback boundari ... Rasca, Anthony; Farrell, William; MacDowall, Robert; Bale, Stuart; Kasper, Justin; Published by: \apj Published on: aug YEAR: 2021 DOI: 10.3847/1538-4357/ac079f The Sun; Solar wind; Solar Physics; 1693; 1534; 1476; Parker Data Used |
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The Dynamic Formation of Pseudostreamers Streamers and pseudostreamers structure the corona at the largest scales, as seen in both eclipse and coronagraph white-light images. Their inverted-goblet appearance encloses broad coronal loops at the Sun and tapers to a narrow radial stalk away from the star. The streamer associated with the global solar dipole magnetic field is long-lived, predominantly contains a single arcade of nested loops within it, and separates opposite-polarity interplanetary magnetic fields with the heliospheric current sheet (HCS) anchored at i ... Scott, Roger; Pontin, David; Antiochos, Spiro; DeVore, Richard; Wyper, Peter; Published by: The Astrophysical Journal Published on: 05/2021 YEAR: 2021 DOI: 10.3847/1538-4357/abec4f Solar Physics; Solar magnetic reconnection; Solar wind; 1476; 1504; 1534; Parker Data Used |
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First Observations of Anomalous Cosmic Rays in to 36 Solar Radii NASA s Parker Solar Probe mission continues to travel closer to the Sun than any prior human-made object, with an expected closest approach of <10 solar radii (<0.046 au) by 2024. On board, the Integrated Science Investigation of the Sun instrument suite makes unprecedented in situ measurements of energetic particles in the near-Sun environment. The current low level of solar activity offers a prime opportunity to measure cosmic rays closer to the Sun than ever before. We present the first observations of anomalous cosmic ra ... Rankin, J.; McComas, D.; Leske, R.; Christian, E.; Cohen, C.; Cummings, A.; Joyce, C.; Labrador, A.; Mewaldt, R.; Posner, A.; Schwadron, N.; Strauss, R.; Stone, E.; Wiedenbeck, M.; Published by: The Astrophysical Journal Published on: 05/2021 YEAR: 2021 DOI: 10.3847/1538-4357/abec7e cosmic rays; Solar wind; Heliosphere; Solar energetic particles; Solar Physics; solar cycle; Quiet Sun; Particle astrophysics; interplanetary magnetic fields; Plasma astrophysics; Interplanetary particle acceleration; Pickup ions; 329; 1534; 711; 1491; 1476; 1487; 1322; 96; 824; 1261; 826; 1239; Parker Data Used |
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Could Switchbacks Originate in the Lower Solar Atmosphere? I. Formation Mechanisms of Switchbacks The recent rediscovery of magnetic field switchbacks or deflections embedded in the solar wind flow by the Parker Solar Probe mission lead to a huge interest in the modeling of the formation mechanisms and origin of these switchbacks. Several scenarios for their generation were put forth, ranging from lower solar atmospheric origins by reconnection, to being a manifestation of turbulence in the solar wind, and so on. Here we study some potential formation mechanisms of magnetic switchbacks in the lower solar atmosphere, usin ... Magyar, Norbert; Utz, Dominik; Erdélyi, Robertus; Nakariakov, Valery; Published by: The Astrophysical Journal Published on: 04/2021 YEAR: 2021 DOI: 10.3847/1538-4357/abec49 Parker Data Used; Solar atmosphere; Solar Physics; Magnetohydrodynamics; 1477; 1476; 1964; Astrophysics - Solar and Stellar Astrophysics |
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Characteristics of Magnetic Holes in the Solar Wind Revealed by Parker Solar Probe Yu, L.; Huang, S.~Y.; Yuan, Z.~G.; Jiang, K.; Xiong, Q.~Y.; Xu, S.~B.; Wei, Y.~Y.; Zhang, J.; Zhang, Z.~H.; Published by: \apj Published on: 02/2021 YEAR: 2021 DOI: 10.3847/1538-4357/abb9a8 Solar wind; Solar Physics; interplanetary magnetic fields; Solar magnetic fields; 1534; 1476; 824; 1503; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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Whistlers in the Solar Vicinity That Are Spiky in Time and Frequency Mozer, F.~S.; Bonnell, J.~W.; Halekas, J.~S.; Rahmati, A.; Schum, G.; Vasko, I.~V.; Published by: \apj Published on: 02/2021 YEAR: 2021 DOI: 10.3847/1538-4357/abce59 Solar wind; Solar Physics; Solar electromagnetic emission; 1534; 1476; 1490 |
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