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Found 691 entries in the Bibliography.
Showing entries from 151 through 200
| 2022 |
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Context. Magnetic switchbacks in the solar wind are large deflections of the magnetic field vector, which often reverse their radial component, and are associated with a velocity spike consistent with their Alfv\ enic nature. The Parker Solar Probe (PSP) mission revealed them to be a dominant feature of the near-Sun solar wind. Where and how they are formed remains unclear and subject to discussion. \ Aims: We investigate the orientation of the magnetic field deflections in switchbacks to determine if they are characterized ... Fargette, Na; Lavraud, Benoit; Rouillard, Alexis; eville, Victor; Bale, Stuart; Kasper, Justin; Published by: \aap Published on: jul YEAR: 2022 DOI: 10.1051/0004-6361/202243537 Parker Data Used; Solar wind; Sun: magnetic fields; Sun: corona; Sun: photosphere; methods: data analysis; methods: statistical; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Structure and fluctuations of a slow ICME sheath observed at 0.5 au by the Parker Solar Probe Context. Sheath regions ahead of interplanetary coronal mass ejections (ICMEs) are compressed and turbulent global heliospheric structures. Their global and fine-scale structure are outstanding research problems, and only a few studies have been conducted on this topic closer to the Sun than 1 au. Comprehensive knowledge of the sheath structure and embedded fluctuations and of their evolution in interplanetary space is important for understanding their geoeffectiveness, their role in accelerating charged particles to high en ... Kilpua, E.~K.~J.; Good, S.~W.; Ala-Lahti, M.; Osmane, A.; Pal, S.; Soljento, J.~E.; Zhao, L.~L.; Bale, S.; Published by: \aap Published on: jul YEAR: 2022 DOI: 10.1051/0004-6361/202142191 Parker Data Used; Solar wind; Sun: coronal mass ejections (CMEs); shock waves; turbulence; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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Searching for a Solar Source of Magnetic-Field Switchbacks in Parker Solar Probe s First Encounter Parker Solar Probe observations show ubiquitous magnetic-field reversals closer to the Sun, often referred to as switchbacks . The switchbacks have been observed before in the solar wind near 1 AU and beyond, but their occurrence was historically rare. PSP measurements below \ensuremath\sim 0.2 AU show that switchbacks are, however, the most prominent structures in the young solar wind. In this work, we analyze remote-sensing observations of a small equatorial coronal hole to which PSP was connected during the perihel ... de Pablos, D.; Samanta, T.; Badman, S.~T.; Schwanitz, C.; Bahauddin, S.~M.; Harra, L.~K.; Petrie, G.; Cormack, Mac; Mandrini, C.~H.; Raouafi, N.~E.; Pillet, Martinez; Velli, M.; Published by: \solphys Published on: jul YEAR: 2022 DOI: 10.1007/s11207-022-02022-4 |
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Switchbacks-abrupt reversals of the magnetic field within the solar wind-have been ubiquitously observed by Parker Solar Probe (PSP). Their origin, whether from processes near the solar surface or within the solar wind itself, remains under debate and likely has key implications for solar wind heating and acceleration. Here, using three-dimensional expanding box simulations, we examine the properties of switchbacks arising from the evolution of outwards-propagating Alfv\ en waves in the expanding solar wind in detail. Our go ... Johnston, Zade; Squire, Jonathan; Mallet, Alfred; Meyrand, Romain; Published by: Physics of Plasmas Published on: jul YEAR: 2022 DOI: 10.1063/5.0097983 Parker Data Used; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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An\ alisis cinem\ atico de una eyecci\ on coronal de masa de 10 a 46 radios solares Di Lorenzo, L.; Balmaceda, L.~A.; Cremades, H.; Published by: Boletin de la Asociacion Argentina de Astronomia La Plata Argentina Published on: jul Parker Data Used; Sun: coronal mass ejections (CMEs); Sun: corona; Sun: heliosphere; solar-terrestrial relations |
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Density and Velocity Fluctuations of Alpha Particles in Magnetic Switchbacks McManus, Michael; Verniero, Jaye; Bale, Stuart; Bowen, Trevor; Larson, Davin; Kasper, Justin; Livi, Roberto; Matteini, Lorenzo; Rahmati, Ali; Romeo, Orlando; Whittlesey, Phyllis; Woolley, Thomas; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac6ba3 Parker Data Used; Heliosphere; Solar wind; Space plasmas; 711; 1534; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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MHD-scale anisotropy in solar wind turbulence near the Sun using Parker solar probe data Recent Parker Solar Probe (PSP) observations have shown the presence of sudden reversals in the radial magnetic field, known as switchbacks. Applying a method based on wavelet analysis, here we study the nature of power and spectral-index anisotropies in switchback and non-switchback intervals using PSP data. While a similar spectral-index anisotropy, consistent with critical balance, is found in the switchback and non-switchback intervals, power anisotropy is more enhanced in the non- switchback samples. This result may be ... Sakshee, Sakshee; Bandyopadhyay, Riddhi; Banerjee, Supratik; Published by: \mnras Published on: jul YEAR: 2022 DOI: 10.1093/mnras/stac1449 Parker Data Used; MHD; turbulence; methods: data analysis; Solar wind |
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Taylor Microscale and Effective Reynolds Number near the Sun from PSP The Taylor microscale is a fundamental length scale in turbulent fluids, representing the end of fluid properties and onset of dissipative processes. The Taylor microscale can also be used to evaluate the Reynolds number in classical turbulence theory. Although the solar wind is weakly collisional, it approximately behaves as a magnetohydrodynamic (MHD) fluid at scales larger than the kinetic scale. As a result, classical fluid turbulence theory and formalisms are often used to study turbulence in the MHD range. Therefore, a ... Phillips, C.; Bandyopadhyay, R.; McComas, D.~J.; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac713f Parker Data Used; Solar wind; interplanetary turbulence; Magnetohydrodynamics; Space plasmas; 1534; 830; 1964; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Quasi-periodic Energy Release and Jets at the Base of Solar Coronal Plumes Coronal plumes are long, ray-like, open structures that have been considered as possible sources of the solar wind. Their origin in the largely unipolar coronal holes has long been a mystery. Earlier spectroscopic and imaging observations revealed blueshifted plasma and propagating disturbances (PDs) in plumes that are widely interpreted in terms of flows and/or propagating slow-mode waves, but these interpretations (flows versus waves) remain under debate. Recently we discovered an important clue about plume internal struct ... Kumar, Pankaj; Karpen, Judith; Uritsky, Vadim; Deforest, Craig; Raouafi, Nour; DeVore, Richard; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac6c24 Parker Data Used; Jets; Solar magnetic reconnection; Solar wind; Solar coronal plumes; 870; 1504; 1534; 2039; Astrophysics - Solar and Stellar Astrophysics |
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Parker Solar Probe detects solar radio bursts related with a behind-the-limb active region Context. The interpretation of solar radio bursts observed by Parker Solar Probe (PSP) in the encounter phase plays a key role in understanding intrinsic properties of the emission mechanism in the solar corona. Lower time-frequency resolution of the PSP receiver can be overcome by simultaneous ground-based observations using more advanced antennas and receivers. \ Aims: In this paper we present such observations for which the active active region 12 765, begetter of type III, J, and U solar bursts, was within sight of groun ... Stanislavsky, Aleksander; Bubnov, Igor; Koval, Artem; Yerin, Serge; Published by: \aap Published on: jan YEAR: 2022 DOI: 10.1051/0004-6361/202141984 Parker Data Used; Sun: activity; Sun: corona; Sun: radio radiation; methods: observational; space vehicles; 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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Inertial-range Magnetic-fluctuation Anisotropy Observed from Parker Solar Probe s First Seven Orbits Solar wind turbulence is anisotropic with respect to the mean magnetic field. Anisotropy leads to ambiguity when interpreting in situ turbulence observations in the solar wind because an apparent change in the measurements could be due to either the change of intrinsic turbulence properties or to a simple change of the spacecraft sampling direction. We demonstrate the ambiguity using the spectral index and magnetic compressibility in the inertial range observed by the Parker Solar Probe during its first seven orbits ranging ... Zhao, L.; Zank, G.~P.; Adhikari, L.; Nakanotani, M.; Published by: \apjl Published on: jan YEAR: 2022 DOI: 10.3847/2041-8213/ac4415 Parker Data Used; 1534; 830; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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We propose a model for interpreting highly variable ion composition ratios in solar energetic particle (SEP) events recently observed by the Parker Solar Probe (PSP) at 0.3-0.45 au. We use numerical simulations to calculate SEP propagation in a turbulent interplanetary magnetic field with a Kolmogorov power spectrum from large scales down to the gyration scale of energetic particles. We show that when the source regions of different species are offset by a distance comparable to the size of the source regions, the observed e ... Guo, Fan; Zhao, Lulu; Cohen, Christina; Giacalone, Joe; Leske, R.~A.; Wiedenbeck, M.~E.; Kahler, S.~W.; Li, Xiaocan; Zhang, Qile; Ho, George; Desai, Mihir; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac3233 Parker Data Used; 1491; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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One of the major discoveries of NASA s 1979-1991 Pioneer Venus Orbiter is that the nightside ionosphere becomes filamentary at high altitude, forming comet-like tail rays. Pioneer Venus Orbiter could not establish how much farther into the wake of Venus tail rays extend, nor understand how they form. Here we present plasma and fields data from the fourth flyby of Venus by NASA s Parker Solar Probe consistent with an intercept with an ionospheric tail ray. The observations unambiguously demonstrate that Venusian Ionotail Rays ... Collinson, Glyn; Ramstad, Robin; Frahm, Rudy; Wilson, Lynn; Xu, Shaosui; Whittlesey, Phyllis; Brecht, Stephen; Ledvina, Stephen; Published by: \grl Published on: jan YEAR: 2022 DOI: 10.1029/2021GL096485 Parker Data Used; Venus; Tail Rays; ionosphere; upper hybrid emission; parker solar probe; Atmospheric escape |
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Suprathermal ions in the corona are thought to serve as seed particles for large gradual solar energetic particle (SEP) events associated with fast and wide coronal mass ejections (CMEs). A better understanding of the role of suprathermal particles as seed populations for SEP events can be made by using observations close to the Sun. We study a series of SEP events observed by the Integrated Science Investigation of the Sun (IS\ensuremath\odotIS) suite on board the Parker Solar Probe (PSP) from 2020 May 27 to June 2, during ... Zhuang, Bin; Lugaz, No\; Lario, David; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac3af2 Parker Data Used; 1491; 310; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Clouds of Spacecraft Debris Liberated by Hypervelocity Dust Impacts on Parker Solar Probe Hypervelocity impacts on spacecraft surfaces produce a wide range of effects including transient plasma clouds, surface material ablation, and for some impacts, the liberation of spacecraft material as debris clouds. This study examines debris-producing impacts on the Parker Solar Probe spacecraft as it traverses the densest part of the zodiacal cloud: the inner heliosphere. Hypervelocity impacts by interplanetary dust grains on the spacecraft that produce debris clouds are identified and examined. Impact-generated plasma an ... Malaspina, David; Stenborg, Guillermo; Mehoke, Doug; Al-Ghazwi, Adel; Shen, Mitchell; Hsu, Hsiang-Wen; Iyer, Kaushik; Bale, Stuart; de Wit, Thierry; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac3bbb |
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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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Using the Parker Solar Probe FIELDS bandpass-filter data and SWEAP electron data from Encounters 1 through 9, we show statistical properties of narrowband whistlers from \raisebox-0.5ex\textasciitilde16 R $_s$ to \raisebox-0.5ex\textasciitilde130 R $_s$, and compare wave occurrence to electron properties including beta, temperature anisotropy, and heat flux. Whistlers are very rarely observed inside \raisebox-0.5ex\textasciitilde28 R $_s$ (\raisebox-0.5ex\textasciitilde0.13 au). Outside 28 R $_s$, they occur within a narrow ... Cattell, C.; Breneman, A.; Dombeck, J.; Hanson, E.; Johnson, M.; Halekas, J.; Bale, S.~D.; de Wit, Dudok; Goetz, K.; Goodrich, K.; Malaspina, D.; Pulupa, M.; Case, T.; Kasper, J.~C.; Larson, D.; Stevens, M.; Whittlesey, P.; Published by: \apjl Published on: jan YEAR: 2022 DOI: 10.3847/2041-8213/ac4015 Parker Data Used; 1534; 1261; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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The electron VDF in the solar wind consists of a Maxwellian core, a suprathermal halo, a field-aligned component strahl, and an energetic superhalo that deviates from the equilibrium. Whistler wave turbulence is thought to resonantly scatter the observed electron velocity distribution. Wave-particle interactions that contribute to Whistler wave turbulence are introduced into a Fokker-Planck kinetic transport equation that describes the interaction between the suprathermal electrons and the Whistler waves. A recent numerical ... Tang, Bofeng; Zank, Gary; Kolobov, Vladimir; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac36c9 |
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Strong Perpendicular Velocity-space Diffusion in Proton Beams Observed by Parker Solar Probe The SWEAP instrument suite on Parker Solar Probe (PSP) has detected numerous proton beams associated with coherent, circularly polarized, ion-scale waves observed by PSP s FIELDS instrument suite. Measurements during PSP Encounters 4-8 revealed pronounced complex shapes in the proton velocity distribution functions (VDFs), in which the tip of the beam undergoes strong perpendicular diffusion, resulting in VDF level contours that resemble a hammerhead. We refer to these proton beams, with their attendant hammerhead fe ... Verniero, J.~L.; Chandran, B.~D.~G.; Larson, D.~E.; Paulson, K.; Alterman, B.~L.; Badman, S.; Bale, S.~D.; Bonnell, J.~W.; Bowen, T.~A.; de Wit, Dudok; Kasper, J.~C.; Klein, K.~G.; Lichko, E.; Livi, R.; McManus, M.~D.; Rahmati, A.; Verscharen, D.; Walters, J.; Whittlesey, P.~L.; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac36d5 Parker Data Used; 1544; 23; 1534; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Based on the Parker Solar Probe mission, this paper presents the observations of two correlations in solar wind turbulence near the Sun for the first time, demonstrating the clear existence of the following two correlations. One is positive correlation between the proton temperature and turbulent magnetic energy density. The other is negative correlation between the spectral index and magnetic helicity. It is found that the former correlation has a maximum correlation coefficient (CC) at the wavenumber k \ensuremath\rho $_ p ... Zhao, G.~Q.; Lin, Y.; Wang, X.~Y.; Feng, H.~Q.; Wu, D.~J.; Kasper, J.~C.; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac3747 |
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A Study of an Equatorial Coronal Hole Observed at the First Parker Solar Probe Perihelion In this study, we present an observational analysis of a coronal hole (CH) observed on 2018 November 1 and solar wind (SW) that originated from it, using the Solar Dynamics Observatory, the Parker Solar Probe (PSP) observations at 68 solar radii, ACE and WIND data at 1 au, and interplanetary scintillation (IPS) observations from 0.2 to 1 au. The CH-originated SW stream was observed by L1 on 2018 November 4 and by PSP on 2018 November 15. We examined the CH for nine Carrington Rotations (CR) and find that the SW stream to rea ... Karna, Nishu; Berger, Mitchell; Asgari-Targhi, Mahboubeh; Paulson, Kristoff; Fujiki, Ken; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac3c46 |
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We utilize the data from the Parker Solar Probe mission at its first perihelion to investigate the three-dimensional (3D) anisotropies and scalings of solar wind turbulence for the total, perpendicular, and parallel magnetic-field fluctuations at kinetic scales in the inner heliosphere. By calculating the five-point second-order structure functions, we find that the three characteristic lengths of turbulence eddies for the total and the perpendicular magnetic-field fluctuations in the local reference frame $(\hatL_\perp ,\ha ... Zhang, J.; Huang, S.~Y.; He, J.~S.; Wang, T.~Y.; Yuan, Z.~G.; Deng, X.~H.; Jiang, K.; Wei, Y.~Y.; Xu, S.~B.; Xiong, Q.~Y.; Lin, R.~T.; Yu, L.; Published by: \apjl Published on: jan YEAR: 2022 DOI: 10.3847/2041-8213/ac4027 |
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Simulation of Plasma Emission in Magnetized Plasmas The recent Parker Solar Probe observations of type III radio bursts show that the effects of the finite background magnetic field can be an important factor in the interpretation of data. In the present paper, the effects of the background magnetic field on the plasma-emission process, which is believed to be the main emission mechanism for solar coronal and interplanetary type III radio bursts, are investigated by means of the particle-in-cell simulation method. The effects of the ambient magnetic field are systematically s ... Lee, Sang-Yun; Yoon, Peter; Lee, Ensang; Tu, Weichao; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac32bb Parker Data Used; 1544; 1534; Astrophysics - Solar and Stellar Astrophysics |
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We report small-scale magnetic flux ropes via the in situ measurements from the Parker Solar Probe during the first six encounters, and present additional analyses to supplement our prior work in Chen et al. These flux ropes are detected by the Grad-Shafranov-based algorithm, with their durations and scale sizes ranging from 10 s to \ensuremath\lesssim1 hr and from a few hundred kilometers to 10$^-3$ au, respectively. They include both static structures and those with significant field-aligned plasma flows. Most structures t ... Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac3487 Parker Data Used; 1858; 830; 1504; 1503; 1534; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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Slow Shock Formation Upstream of Reconnecting Current Sheets The formation, development, and impact of slow shocks in the upstream regions of reconnecting current layers are explored. Slow shocks have been documented in the upstream regions of magnetohydrodynamic (MHD) simulations of magnetic reconnection as well as in similar simulations with the kglobal kinetic macroscale simulation model. They are therefore a candidate mechanism for preheating the plasma that is injected into the current layers that facilitate magnetic energy release in solar flares. Of particular interest is their ... Arnold, H.; Drake, J.~F.; Swisdak, M.; Guo, F.; Dahlin, J.~T.; Zhang, Q.; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac423b Parker Data Used; 1504; 2086; 2089; 1544; Physics - Plasma Physics; Physics - Space Physics |
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Improving the Alfv\ en Wave Solar Atmosphere Model Based on Parker Solar Probe Data In van der Holst et al. (2019), we modeled the solar corona and inner heliosphere of the first encounter of NASA s Parker Solar Probe (PSP) using the Alfv\ en Wave Solar atmosphere Model (AWSoM) with Air Force Data Assimilative Photospheric flux Transport- Global Oscillation Network Group magnetograms, and made predictions of the state of the solar wind plasma for the first encounter. AWSoM uses low-frequency Alfv\ en wave turbulence to address the coronal heating and acceleration. Here, we revise our simulations, by introdu ... van der Holst, B.; Huang, J.; Sachdeva, N.; Kasper, J.~C.; Manchester, W.~B.; Borovikov, D.; Chandran, B.~D.~G.; Case, A.~W.; Korreck, K.~E.; Larson, D.; Livi, R.; Stevens, M.; Whittlesey, P.; Bale, S.~D.; Pulupa, M.; Malaspina, D.~M.; Bonnell, J.~W.; Harvey, P.~R.; Goetz, K.; MacDowall, R.~J.; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac3d34 |
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A Fundamental Instability for the Solar Wind As has been known nearly since the beginning of space research with satellites and rockets that the temperature of the atmosphere of our Sun rises rapidly from the photosphere at about 6000 K to the order of 10$^6$ K. The major heating of the solar wind apparently occurs in a narrow region, the transition region, just above the chromosphere, a region where remote sensing of atomic energy levels shows a temperature of 10$^6$ deg. However, since the early days of the recognition of the solar wind it has been recognized that th ... Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac32e0 |
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Parker Solar Probe Imaging of the Night Side of Venus We present images of Venus from the Wide-Field Imager for Parker Solar Probe (WISPR) telescope on board the Parker Solar Probe (PSP) spacecraft, obtained during PSP s third and fourth flybys of Venus on 2020 July 11 and 2021 February 20, respectively. Thermal emission from the surface is observed on the night side, representing the shortest wavelength observations of this emission ever, the first detection of the Venusian surface by an optical telescope observing below 0.8 \ensuremath\mum. Consistent with previous observatio ... Wood, Brian; Hess, Phillip; Lustig-Yaeger, Jacob; Gallagher, Brendan; Korwan, Daniel; Rich, Nathan; Stenborg, Guillermo; Thernisien, Arnaud; Qadri, Syed; Santiago, Freddie; Peralta, Javier; Arney, Giada; Izenberg, Noam; Vourlidas, Angelos; Linton, Mark; Howard, Russell; Raouafi, Nour; Published by: \grl Published on: feb YEAR: 2022 DOI: 10.1029/2021GL096302 |
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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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Recent in situ observations from the Parker Solar Probe (PSP) mission in the inner heliosphere near perihelia show evidence of ion beams, temperature anisotropies, and kinetic wave activity, which are likely associated with kinetic heating and acceleration processes of the solar wind. In particular, the proton beams were detected by PSP/Solar Probe Analyzers-Ion (SPAN-I) and related magnetic fluctuation spectra associated with ion-scale waves were observed by the FIELDS instrument. We present the ion velocity distribution fu ... Ofman, Leon; Boardsen, Scott; Jian, Lan; Verniero, Jaye; Larson, Davin; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac402c Parker Data Used; 1534; 1545; 1544; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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The von K\ arm\ an-Howarth equations give a starting basis for the classical turbulence theory. The formula for the magnetohydrodynamics von K\ arm\ an decay rate represents an energy source in many solar wind models with turbulence as the driver. However, it still lacks the radial trend comparison between the von K\ arm\ an decay rate, the energy supply rate, and the perpendicular heating rate based on direct observations of the solar wind. Here we carry out this kind of comparison for the first time using Parker Solar Prob ... Wu, Honghong; Tu, Chuanyi; He, Jiansen; Wang, Xin; Yang, Liping; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac4413 |
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We analyze the micro-kinetic stability of the electron strahl in the solar wind depending on heliocentric distance. The oblique fast- magnetosonic/whistler (FM/W) instability has emerged in the literature as a key candidate mechanism for the effective scattering of the electron strahl into the electron halo population. Using data from the Parker Solar Probe (PSP) and Helios, we compare the measured strahl properties with the analytical thresholds for the oblique FM/W instability in the low- and high-\ensuremath\beta $_\ensur ... Jeong, Seong-Yeop; Abraham, Joel; Verscharen, Daniel; Ber\vci\vc, Laura; Stansby, David; Nicolaou, Georgios; Owen, Christopher; Wicks, Robert; Fazakerley, Andrew; Rueda, Jeffersson; Bakrania, Mayur; Published by: \apjl Published on: feb YEAR: 2022 DOI: 10.3847/2041-8213/ac4dff Parker Data Used; 1534; 1544; 711; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Flux Rope Merging and the Structure of Switchbacks in the Solar Wind A major discovery of Parker Solar Probe (PSP) was the presence of large numbers of localized increases in the radial solar wind speed and associated sharp deflections of the magnetic field- switchbacks (SBs). A possible generation mechanism of SBs is through magnetic reconnection between open and closed magnetic flux near the solar surface, termed interchange reconnection, that leads to the ejection of flux ropes (FRs) into the solar wind. Observations also suggest that SBs undergo merging, consistent with an FR picture of t ... Agapitov, O.~V.; Drake, J.~F.; Swisdak, M.; Bale, S.~D.; Horbury, T.~S.; Kasper, J.~C.; MacDowall, R.~J.; Mozer, F.~S.; Phan, T.~D.; Pulupa, M.; Raouafi, N.~E.; Velli, M.; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac4016 Parker Data Used; 711; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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At the end of 2020 September, the Parker Solar Probe (PSP) and BepiColombo were radially aligned: PSP was orbiting near 0.17 au and BepiColombo near 0.6 au. This geometry is of particular interest for investigating the evolution of solar wind properties at different heliocentric distances by observing the same solar wind plasma parcels. In this work, we use the magnetic field observations from both spacecraft to characterize both the topology of the magnetic field at different heliocentric distances (scalings, high-order sta ... Alberti, Tommaso; Milillo, Anna; Heyner, Daniel; Hadid, Lina; Auster, Hans-Ulrich; Richter, Ingo; Narita, Yasuhito; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac478d Parker Data Used; 1534; 994; 1964; 830 |
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In the lower solar coronal regions where the magnetic field is dominant, the Alfv\ en speed is much higher than the wind speed. In contrast, the near-Earth solar wind is strongly super- Alfv\ enic, i.e., the wind speed greatly exceeds the Alfv\ en speed. The transition between these regimes is classically described as the Alfv\ en point but may in fact occur in a distributed Alfv\ en critical region. NASA s Parker Solar Probe (PSP) mission has entered this region, as it follows a series of orbits that gradually approach ... Bandyopadhyay, R.; Matthaeus, W.~H.; McComas, D.~J.; Chhiber, R.; Usmanov, A.~V.; Huang, J.; Livi, R.; Larson, D.~E.; Kasper, J.~C.; Case, A.~W.; Stevens, M.; Whittlesey, P.; Romeo, O.~M.; Bale, S.~D.; Bonnell, J.~W.; de Wit, Dudok; Goetz, K.; Harvey, P.~R.; MacDowall, R.~J.; Malaspina, D.~M.; Pulupa, M.; Published by: \apjl Published on: feb YEAR: 2022 DOI: 10.3847/2041-8213/ac4a5c Parker Data Used; 1544; 1534; 824; 23; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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In this paper we examine a low-energy solar energetic particle (SEP) event observed by IS\ensuremath\odotIS s Energetic Particle Instrument-Low (EPI-Lo) inside 0.18 au on 2020 September 30. This small SEP event has a very interesting time profile and ion composition. Our results show that the maximum energy and peak in intensity are observed mainly along the open radial magnetic field. The event shows velocity dispersion, and strong particle anisotropies are observed throughout the event, showing that more particles are stre ... Getachew, T.; McComas, D.~J.; Joyce, C.~J.; Palmerio, E.; Christian, E.~R.; Cohen, C.~M.~S.; Desai, M.~I.; Giacalone, J.; Hill, M.~E.; Matthaeus, W.~H.; McNutt, R.~L.; Mitchell, D.~G.; Mitchell, J.~G.; Rankin, J.~S.; Roelof, E.~C.; Schwadron, N.~A.; Szalay, J.~R.; Zank, G.~P.; Zhao, L.; Lynch, B.~J.; Phan, T.~D.; Bale, S.~D.; Whittlesey, P.~L.; Kasper, J.~C.; Published by: \apj Published on: feb YEAR: 2022 DOI: 10.3847/1538-4357/ac408f Parker Data Used; 1491; 310; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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Observations of cross scale energy transfer in the inner heliosphere by Parker Solar Probe The solar wind, a continuous flow of plasma from the sun, not only shapes the near Earth space environment but also serves as a natural laboratory to study plasma turbulence in conditions that are not achievable in the lab. Starting with the Mariners, for more than five decades, multiple space missions have enabled in- depth studies of solar wind turbulence. Parker Solar Probe (PSP) was launched to explore the origins and evolution of the solar wind. With its state-of-the-art instrumentation and unprecedented close approache ... Parashar, Tulasi; Matthaeus, William; Published by: Reviews of Modern Plasma Physics Published on: dec YEAR: 2022 DOI: 10.1007/s41614-022-00097-x Parker Data Used; Physics - Space Physics; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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Acceleration of polytropic solar wind: Parker Solar Probe observation and one-dimensional model The acceleration of the solar coronal plasma to supersonic speeds is one of the most fundamental yet unresolved problems in heliophysics. Despite the success of Parker s pioneering theory on an isothermal solar corona, the realistic solar wind is observed to be non-isothermal, and the decay of its temperature with radial distance usually can be fitted to a polytropic model. In this work, we use Parker Solar Probe data from the first nine encounters to estimate the polytropic index of solar wind protons. The estimated polytro ... Shi, Chen; Velli, Marco; Bale, Stuart; eville, Victor; c, Milan; Dakeyo, Jean-Baptiste; Published by: Physics of Plasmas Published on: dec YEAR: 2022 DOI: 10.1063/5.0124703 Parker Data Used; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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The Imprint of Intermittent Interchange Reconnection on the Solar Wind The solar wind is known to be highly structured in space and time. Observations from Parker Solar Probe have revealed an abundance of so-called magnetic switchbacks within the near-Sun solar wind. In this Letter, we use a high-resolution, adaptive-mesh, magnetohydrodynamics simulation to explore the disturbances launched into the solar wind by intermittent/bursty interchange reconnection and how they may be related to magnetic switchbacks. We find that repeated ejection of plasmoid flux ropes into the solar wind produces a c ... Wyper, Peter; DeVore, C.~R.; Antiochos, S.~K.; Pontin, D.~I.; Higginson, Aleida; Scott, Roger; Masson, Sophie; Pelegrin-Frachon, Theo; Published by: \apjl Published on: dec YEAR: 2022 DOI: 10.3847/2041-8213/aca8ae Parker Data Used; Solar corona; Solar coronal holes; Solar wind; Solar magnetic reconnection; Solar magnetic fields; Solar Physics; 1483; 1484; 1534; 1504; 1503; 1476 |
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Thermal Energy Budget of Electrons in the Inner Heliosphere: Parker Solar Probe Observations We present an observational analysis of the electron thermal energy budget using data from Parker Solar Probe. We use the macroscopic moments, obtained from our fits to the measured electron distribution function, to evaluate the thermal energy budget based on the second moment of the Boltzmann equation. We separate contributions to the overall budget from reversible and irreversible processes. We find that an irreversible thermal energy source must be present in the inner heliosphere over the heliocentric distance range fro ... Abraham, Joel; Verscharen, Daniel; Wicks, Robert; Rueda, Jeffersson; Owen, Christopher; Nicolaou, Georgios; Jeong, Seong-Yeop; Published by: \apj Published on: dec YEAR: 2022 DOI: 10.3847/1538-4357/ac9fd8 Parker Data Used; The Sun; Solar wind; Heliosphere; Plasma physics; 1693; 1534; 711; 2089; Astrophysics - Solar and Stellar Astrophysics; Physics - Geophysics; Physics - Plasma Physics; Physics - Space Physics |
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We present a 2D kinematic model to study the acceleration of solar energetic particles (SEPs) at a shock driven by a coronal mass ejection. The shock is assumed to be spherical about an origin that is offset from the center of the Sun. This leads to a spatial and temporal evolution of the angle between the magnetic field and the shock-normal direction (\ensuremath\theta $_ Bn $) as it propagates through the Parker spiral magnetic field from the lower corona to 1 au. We find that the high-energy SEP intensity varies significa ... Chen, Xiaohang; Giacalone, Joe; Guo, Fan; Published by: \apj Published on: dec YEAR: 2022 DOI: 10.3847/1538-4357/ac9f43 Parker Data Used; Solar energetic particles; Solar coronal mass ejection shocks; Interplanetary shocks; 1491; 1997; 829; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics; Physics - Space Physics |
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Statistical classification of the Helios solar wind observations into several populations sorted by bulk speed has revealed an outward acceleration of the wind. The faster the wind, the smaller this acceleration in the 0.3-1 au radial range. In this paper, we show that recent measurements from the Parker Solar Probe (PSP) are compatible with an extension closer to the Sun of the latter Helios classification. For instance, the well-established bulk speed/proton temperature (u, T $_p$) correlation and bulk speed/electron tempe ... Dakeyo, Jean-Baptiste; Maksimovic, Milan; emoulin, Pascal; Halekas, Jasper; Stevens, Michael; Published by: \apj Published on: dec YEAR: 2022 DOI: 10.3847/1538-4357/ac9b14 Parker Data Used; Solar wind; Interplanetary particle acceleration; Slow solar wind; Astronomy data modeling; 1534; 826; 1873; 1859 |
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Context. The opacity of the ionosphere prevents comprehensive Earth- based surveys of low frequency \ensuremath\nu \ensuremath\lesssim 10 MHz astrophysical radio emissions. The limited available data in this frequency regime show a downturn in the mean sky brightness at \ensuremath\nu \ensuremath\lesssim 3 MHz in a divergence from the synchrotron emission power-law that is observed at higher frequencies. The turning over of the spectrum coincides with a shift in the region of maximum brightness from the Galactic plane to the ... Page, B.; Bassett, N.; Lecacheux, A.; Pulupa, M.; Rapetti, D.; Bale, S.~D.; Published by: \aap Published on: dec YEAR: 2022 DOI: 10.1051/0004-6361/202244621 Parker Data Used; radio continuum: ISM; Galaxy: disk; opacity; methods: data analysis |
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Switchbacks — abrupt reversals of the magnetic field within the solar wind — have been ubiquitously observed by Parker Solar Probe (PSP). Their origin, whether from processes near the solar surface or within the solar wind itself, remains under debate, and likely has key implications for solar wind heating and acceleration. Here, using three-dimensional expanding box simulations, we examine the properties of switchbacks arising from the evolution of outwards-propagating Alfv\ en waves in the expanding solar wind ... Johnston, Zade; Squire, Jonathan; Mallet, Alfred; Meyrand, Romain; Published by: Physics of Plasmas Published on: dec YEAR: 2022 DOI: 10.1063/5.0133296 Parker Data Used; Astrophysics - Solar and Stellar Astrophysics; Physics - Plasma Physics |
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Direct detection of ultralight dark matter bound to the Sun with space quantum sensors Recent advances in quantum sensors, including atomic clocks, enable searches for a broad range of dark matter candidates. The question of the dark matter distribution in the Solar system critically affects the reach of dark matter direct detection experiments. Partly motivated by the NASA Deep Space Atomic Clock and the Parker Solar Probe, we show that space quantum sensors present new opportunities for ultralight dark matter searches, especially for dark matter states bound to the Sun. We show that space quantum sensors can ... Tsai, Yu-Dai; Eby, Joshua; Safronova, Marianna; Published by: Nature Astronomy Published on: dec YEAR: 2022 DOI: 10.1038/s41550-022-01833-6 Parker Data Used; High Energy Physics - Phenomenology; Astrophysics - Cosmology and Nongalactic Astrophysics; Physics - Atomic Physics |
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Using ion measurements from Ultra-Low-Energy Isotope Spectrometer observations on board Advanced Composition Explorer and Solar Isotope Spectrometer observations on board the Solar Terrestrial Observatory (STEREO)-A and STEREO-B spacecraft, we have identified 854 $^3$He-rich time periods between 1997 September and 2021 March. We include all event types with observed $^3$He enhancements such as corotating interaction regions, gradual solar energetic particle (SEP) events, interplanetary shocks, and impulsive SEP events. We em ... Hart, S.~T.; Dayeh, M.~A.; ik, Bu\vc\; Desai, M.~I.; Ebert, R.~W.; Ho, G.~C.; Li, G.; Mason, G.~M.; Published by: \apjs Published on: dec YEAR: 2022 DOI: 10.3847/1538-4365/ac91c1 Parker Data Used; Active sun; Solar energetic particles; Active Solar Corona; Solar atmosphere; Solar abundances; Heliosphere; Solar observatories; 18; 1491; 1988; 1477; 1474; 711; 1513; Astrophysics - Solar and Stellar Astrophysics; Physics - Space Physics |
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We study the radial evolution, from 0.1 AU to the Earth, of a homogeneous recurrent fast wind, coming from the same source on the Sun, by means of new measurements by both Solar Orbiter and Parker Solar Probe. With respect to previous radial studies, we extend, for the first time, the analysis of a recurrent fast stream at distances never reached prior to the Parker Solar Probe mission. Confirming previous findings, the observations show: (i) a decrease in the radial trend of the proton density that is slower than the one ex ... Perrone, D.; Perri, S.; Bruno, R.; Stansby, D.; Amicis, R.; Jagarlamudi, V.~K.; Laker, R.; Toledo-Redondo, S.; Stawarz, J.~E.; Telloni, D.; De Marco, R.; Owen, C.~J.; Raines, J.~M.; Settino, A.; Lavraud, B.; Maksimovic, M.; Vaivads, A.; Phan, T.~D.; Fargette, N.; Louarn, P.; Zouganelis, I.; Published by: \aap Published on: dec YEAR: 2022 DOI: 10.1051/0004-6361/202243989 |
