# PSP Bibliography

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## Found 70 entries in the Bibliography.

### Showing entries from 1 through 50

 2022 Inhomogeneous Kinetic Alfv\ en Waves in the Near-Sun Solar Wind Intervals of intense electromagnetic, broadband plasma waves are reported in the near-Sun solar wind. These waves are identified as kinetic Alfv\ en waves (KAWs), based on comparison between data and theory for their observed electric- to magnetic-field ratio, and magnetic compressibility, as a function of frequency. In contrast to KAW observations at 1 au, KAWs in the near-Sun solar wind are found to be spatially inhomogeneous, preferentially occurring where the ambient magnetic field experiences strong deviations from the ... Malaspina, David; Chasapis, Alexandros; Tatum, Peter; Salem, Chadi; Bale, Stuart; Bonnell, John; de Wit, Thierry; Goetz, Keith; Pulupa, Marc; Halekas, Jasper; Whittlesey, Phyllis; Livi, Roberto; Case, Anthony; Stevens, Michael; Larson, Davin; Published by: \apj      Published on: sep YEAR: 2022     DOI: 10.3847/1538-4357/ac87a7 Galactic Cosmic-Ray Propagation in the Inner Heliosphere: Improved Force-field Model Li, Jung-Tsung; Beacom, John; Peter, Annika; Published by: \apj      Published on: sep YEAR: 2022     DOI: 10.3847/1538-4357/ac8cf3 Modeling of Joint Parker Solar Probe-Metis/Solar Orbiter Observations We present the first theoretical modeling of joint Parker Solar Probe (PSP)-Metis/Solar Orbiter (SolO) quadrature observations. The combined observations describe the evolution of a slow solar wind plasma parcel from the extended solar corona (3.5-6.3 R $_\ensuremath\odot$) to the very inner heliosphere (23.2 R $_\ensuremath\odot$). The Metis/SolO instrument remotely measures the solar wind speed finding a range from 96 to 201 km s$^-1$, and PSP measures the solar wind plasma in situ, observing a radial speed of 219.34 km s$... Adhikari, L.; Zank, G.~P.; Telloni, D.; Zhao, L.; Published by: \apjl Published on: oct YEAR: 2022 DOI: 10.3847/2041-8213/ac91c6 Strategies for Determining the Cascade Rate in MHD Turbulence: Isotropy, Anisotropy, and Spacecraft Sampling Exact laws for evaluating cascade rates, tracing back to the Kolmogorov 4/5 law, have been extended to many systems of interest including magnetohydrodynamics (MHD), and compressible flows of the magnetofluid and ordinary fluid types. It is understood that implementations may be limited by the quantity of available data and by the lack of turbulence symmetry. Assessment of the accuracy and feasibility of such third-order (or Yaglom) relations is most effectively accomplished by examining the von K\ arm\ an-Howarth equati ... Wang, Yanwen; Chhiber, Rohit; Adhikari, Subash; Yang, Yan; Bandyopadhyay, Riddhi; Shay, Michael; Oughton, Sean; Matthaeus, William; Cuesta, Manuel; Published by: \apj Published on: oct YEAR: 2022 DOI: 10.3847/1538-4357/ac8f90 Higher-order Turbulence Statistics in the Sub-Alfv\ enic Solar Wind Observed by Parker Solar Probe Parker Solar Probe has been the first spacecraft to enter the deep corona below the Alfv\ en critical point. Here we examine the higher-order statistical properties of magnetic-field fluctuations in the sub-Alfv\ enic solar wind and compare the results with the neighboring super-Alfv\ enic region. The intermittency and multifractal properties are analyzed by inspecting the probability density functions, the scale- dependent kurtosis, and fractal spectrum of magnetic-field fluctuations. It is found that the magnetic-field flu ... Zhang, J.; Huang, S.~Y.; Yuan, Z.~G.; Jiang, K.; Xu, S.~B.; Bandyopadhyay, R.; Wei, Y.~Y.; Xiong, Q.~Y.; Wang, Z.; Yu, L.; Lin, R.~T.; Published by: \apj Published on: oct YEAR: 2022 DOI: 10.3847/1538-4357/ac8c34 Observation and Modeling of the Solar Wind Turbulence Evolution in the Sub-Mercury Inner Heliosphere Telloni, Daniele; Adhikari, Laxman; Zank, Gary; Hadid, Lina; anchez-Cano, Beatriz; Sorriso-Valvo, Luca; Zhao, Lingling; Panasenco, Olga; Shi, Chen; Velli, Marco; Susino, Roberto; Verscharen, Daniel; Milillo, Anna; Alberti, Tommaso; Narita, Yasuhito; Verdini, Andrea; Grimani, Catia; Bruno, Roberto; Amicis, Raffaella; Perrone, Denise; Marino, Raffaele; Carbone, Francesco; Califano, Francesco; Malara, Francesco; Stawarz, Julia; Laker, Ronan; Liberatore, Alessandro; Bale, Stuart; Kasper, Justin; Heyner, Daniel; de Wit, Thierry; Goetz, Keith; Harvey, Peter; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Case, Anthony; Korreck, Kelly; Larson, Davin; Livi, Roberto; Stevens, Michael; Whittlesey, Phyllis; Auster, Hans-Ulrich; Richter, Ingo; Published by: \apjl Published on: oct YEAR: 2022 DOI: 10.3847/2041-8213/ac9624 Cross-scale Correlations in Imbalanced Solar Wind Turbulence: Parker Solar Probe Observations Zhao, G.~Q.; Meyrand, R.; Feng, H.~Q.; Wu, D.~J.; Kasper, J.~C.; Published by: \apj Published on: oct YEAR: 2022 DOI: 10.3847/1538-4357/ac9380 2D and Slab Turbulent Cascade Rates in the Inner Heliosphere Adhikari, L.; Zank, G.~P.; Zhao, L.; Telloni, D.; Published by: \apj Published on: oct YEAR: 2022 DOI: 10.3847/1538-4357/ac9234 Reconciling Parker Solar Probe Observations and Magnetohydrodynamic Theory The Parker Solar Probe mission provides a unique opportunity to characterize several features of the solar wind at different heliocentric distances. Recent findings have shown a transition in the inertial range spectral and scaling properties around 0.4-0.5 au when moving away from the Sun. Here we provide, for the first time, how to reconcile these observational results on the radial evolution of the magnetic and velocity field fluctuations with two scenarios drawn from the magnetohydrodynamic theory. The observed breakdown ... Alberti, Tommaso; Benella, Simone; Consolini, Giuseppe; Stumpo, Mirko; Benzi, Roberto; Published by: \apjl Published on: nov YEAR: 2022 DOI: 10.3847/2041-8213/aca075 Observations of Quiescent Solar Wind Regions with Near-f$_ce$Wave Activity In situ measurements in the near-Sun solar wind from the Parker Solar Probe have revealed the existence of quiescent solar wind regions: extended regions of solar wind with low-amplitude turbulent magnetic field fluctuations compared to adjacent regions. Identified through the study of harmonic waves near the electron cyclotron frequency (f$_ce$), these quiescent regions are shown to host a variety of plasma waves. The near-f$_ce$harmonic waves are observed exclusively in quiescent regions, and as such, they can be used a ... Short, Benjamin; Malaspina, David; Halekas, Jasper; Romeo, Orlando; Verniero, J.~L.; Finley, Adam; Kasper, Justin; Rahmati, Ali; Bale, Stuart; Bonnell, John; Case, Anthony; de Wit, Thierry; Goetz, Keith; Goodrich, Katherine; Harvey, Peter; Korreck, Kelly; Larson, Davin; Livi, Roberto; MacDowall, Robert; Pulupa, Marc; Stevens, Michael; Whittlesey, Phyllis; Published by: \apj Published on: nov YEAR: 2022 DOI: 10.3847/1538-4357/ac97e4 Anisotropic Magnetic Turbulence in the Inner Heliosphere-Radial Evolution of Distributions Observed by Parker Solar Probe Observations from Parker Solar Probe s first five orbits are used to investigate the helioradial evolution of probability density functions (pdfs) of fluctuations of magnetic-field components between \raisebox-0.5ex\textasciitilde28 and 200 R$_\ensuremath\odot$. Transformation of the magnetic-field vector to a local mean-field coordinate system permits examination of anisotropy relative to the mean magnetic-field direction. Attention is given to effects of averaging-interval size. It is found that pdfs of the perpendicular ... Chhiber, Rohit; Published by: \apj Published on: nov YEAR: 2022 DOI: 10.3847/1538-4357/ac9386 Ion Kinetics of Plasma Flows: Earth s Magnetosheath versus Solar Wind Revealing the formation, dynamics, and contribution to plasma heating of magnetic field fluctuations in the solar wind is an important task for heliospheric physics and for a general plasma turbulence theory. Spacecraft observations in the solar wind are limited to spatially localized measurements, so that the evolution of fluctuation properties with solar wind propagation is mostly studied via statistical analyses of data sets collected by different spacecraft at various radial distances from the Sun. In this study we inves ... Artemyev, A.~V.; Shi, C.; Lin, Y.; Nishimura, Y.; Gonzalez, C.; Verniero, J.; Wang, X.; Velli, M.; Tenerani, A.; Sioulas, N.; Published by: \apj Published on: nov YEAR: 2022 DOI: 10.3847/1538-4357/ac96e4 Intermittency in the Expanding Solar Wind: Observations from Parker Solar Probe (0.16 au), Helios 1 (0.3-1 au), and Voyager 1 (1-10 au) We examine statistics of magnetic-field vector components to explore how intermittency evolves from near-Sun plasma to radial distances as large as 10 au. Statistics entering the analysis include autocorrelation, magnetic structure functions of the order of n (SF$_ n $), and scale-dependent kurtosis (SDK), each grouped in ranges of heliocentric distance. The Goddard Space Flight Center Space Physics Data Facility provides magnetic-field measurements for resolutions of 6.8 ms for Parker Solar Probe, 6 s for Helios, and 1.92 s ... Cuesta, Manuel; Parashar, Tulasi; Chhiber, Rohit; Matthaeus, William; Published by: \apjs Published on: mar YEAR: 2022 DOI: 10.3847/1538-4365/ac45fa Energy Transfer, Discontinuities, and Heating in the Inner Heliosphere Measured with a Weak and Local Formulation of the Politano-Pouquet Law The solar wind is a highly turbulent plasma for which the mean rate of energy transfer ɛ has been measured for a long time using the Politano-Pouquet (PP98) exact law. However, this law assumes statistical homogeneity that can be violated by the presence of discontinuities. Here, we introduce a new method based on the inertial dissipation$ D _I^{\sigma }$whose analytical form is derived from incompressible magnetohydrodynamics; it can be considered as a weak and local (in space) formulation of the PP98 law whose expressio ... David, V.; Galtier, S.; Sahraoui, F.; Hadid, L.~Z.; Published by: \apj Published on: mar YEAR: 2022 DOI: 10.3847/1538-4357/ac524b The Effect of the Fluctuating Interplanetary Magnetic Field on the Cosmic Ray Intensity Profile of the Ground-level Enhancement (GLE) Events We numerically integrate the equations of motion of a large number of GeV protons, released impulsively near the Sun, in order to study their time-intensity behavior at the location of an observer at 1 au. This is relevant to the interpretation of Ground Level Enhancements (GLEs) detected by neutron monitors on Earth. Generally, the observed time-intensity profiles reveal a single sharp rise, followed by slow decay. However, in the 1989 October 22 GLE event, there was an initial sharp spike followed by a secondary smaller sp ... Moradi, Ashraf; Giacalone, Joe; Published by: \apj Published on: jun YEAR: 2022 DOI: 10.3847/1538-4357/ac66e0 Isotropization and Evolution of Energy-containing Eddies in Solar Wind Turbulence: Parker Solar Probe, Helios 1, ACE, WIND, and Voyager 1 We examine the radial evolution of correlation lengths perpendicular ($\lambda _C^\perp $) and parallel ($\lambda _C^\parallel ) to the magnetic-field direction, computed from solar wind magnetic-field data measured by Parker Solar Probe (PSP) during its first eight orbits, Helios 1, Advanced Composition Explorer (ACE), WIND, and Voyager 1 spacecraft. Correlation lengths are grouped by an interval s alignment angle; the angle between the magnetic-field and solar wind velocity vectors (\ensuremath\Theta_BV). Parallel a ... Cuesta, Manuel; Chhiber, Rohit; Roy, Sohom; Goodwill, Joshua; Pecora, Francesco; Jarosik, Jake; Matthaeus, William; Parashar, Tulasi; Bandyopadhyay, Riddhi; Published by: \apjl Published on: jun YEAR: 2022 DOI: 10.3847/2041-8213/ac73fd Growth of Outward Propagating Fast-magnetosonic/Whistler Waves in the Inner Heliosphere Observed by Parker Solar Probe The solar wind in the inner heliosphere has been observed by Parker Solar Probe (PSP) to exhibit abundant wave activities. The cyclotron wave modes responding to ions or electrons are among the most crucial wave components. However, their origin and evolution in the inner heliosphere close to the Sun remains a mystery. Specifically, it remains unknown whether it is an emitted signal from the solar atmosphere or an eigenmode growing locally in the heliosphere due to plasma instability. To address and resolve this controversy, ... He, Jiansen; Wang, Ying; Zhu, Xingyu; Duan, Die; Verscharen, Daniel; Zhao, Guoqing; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac6c8e On the Transmission of Turbulent Structures across the Earth s Bow Shock Collisionless shocks and plasma turbulence are crucial ingredients for a broad range of astrophysical systems. The shock-turbulence interaction, and in particular the transmission of fully developed turbulence across the quasi-perpendicular Earth s bow shock, is here addressed using a combination of spacecraft observations and local numerical simulations. An alignment between the Wind (upstream) and Magnetospheric Multiscale (downstream) spacecraft is used to study the transmission of turbulent structures across the shock, r ... Trotta, Domenico; Pecora, Francesco; Settino, Adriana; Perrone, Denise; Hietala, Heli; Horbury, Timothy; Matthaeus, William; Burgess, David; Servidio, Sergio; Valentini, Francesco; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac7798 MHD Turbulent Power Anisotropy in the Inner Heliosphere We study anisotropic magnetohydrodynamic (MHD) turbulence in the slow solar wind measured by Parker Solar Probe (PSP) and Solar Orbiter (SolO) during its first orbit from the perspective of variance anisotropy and correlation anisotropy. We use the Belcher \& Davis approach (M1) and a new method (M2) that decomposes a fluctuating vector into parallel and perpendicular fluctuating vectors. M1 and M2 calculate the transverse and parallel turbulence components relative to the mean magnetic field direction. The parallel turbulen ... Adhikari, L.; Zank, G.~P.; Zhao, L.; Telloni, D.; Published by: \apj Published on: jul YEAR: 2022 DOI: 10.3847/1538-4357/ac70cb 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 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 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 Two Correlations with Enhancement Near the Proton Gyroradius Scale in Solar Wind Turbulence: Parker Solar Probe (PSP) and Wind Observations 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 Three-Dimensional Anisotropy and Scaling Properties of Solar Wind Turbulence at Kinetic Scales in the Inner Heliosphere: Parker Solar Probe Observations 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 $(\hatL_\perp ,\ha ... Zhang, J.; Huang, S.~Y.; He, J.~S.; Wang, T.~Y.; Yuan, Z.~G.; Deng, X.~H.; Jiang, K.; Wei, Y.~Y.; Xu, S.~B.; Xiong, Q.~Y.; Lin, R.~T.; Yu, L.; Published by: \apjl Published on: jan YEAR: 2022 DOI: 10.3847/2041-8213/ac4027 Small-scale Magnetic Flux Ropes and Their Properties Based on In Situ Measurements from the Parker Solar Probe We report small-scale magnetic flux ropes via the in situ measurements from the Parker Solar Probe during the first six encounters, and present additional analyses to supplement our prior work in Chen et al. These flux ropes are detected by the Grad-Shafranov-based algorithm, with their durations and scale sizes ranging from 10 s to \ensuremath\lesssim1 hr and from a few hundred kilometers to 10$^-3au, respectively. They include both static structures and those with significant field-aligned plasma flows. Most structures t ... Chen, Yu; Hu, Qiang; Published by: \apj Published on: jan YEAR: 2022 DOI: 10.3847/1538-4357/ac3487 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 Consistency of von Karman Decay Rate with the Energy Supply Rate and Heating Rate Observed by Parker Solar Probe 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 The Singular Behavior of the Solar Wind Scaling Features during Parker Solar Probe-BepiColombo Radial Alignment 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 Magnetic Field Intermittency in the Solar Wind: Parker Solar Probe and SolO Observations Ranging from the Alfv\ en Region up to 1 AU 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 $; SDK), but no clear trend is observed at larger scales. However, lower-order moment-based methods (e.g., partial variance of increments; PVI) are deemed more appropriate for examining the evolution of the bulk of coherent structures (CSs), PVI \ensuremath\geq 3 ... Sioulas, Nikos; Huang, Zesen; Velli, Marco; Chhiber, Rohit; Cuesta, Manuel; Shi, Chen; Matthaeus, William; Bandyopadhyay, Riddhi; Vlahos, Loukas; Bowen, Trevor; Qudsi, Ramiz; Bale, Stuart; Owen, Christopher; Louarn, P.; Fedorov, A.; c, Milan; Stevens, Michael; Case, Anthony; Kasper, Justin; Larson, Davin; Pulupa, Marc; Livi, Roberto; Published by: \apj Published on: aug YEAR: 2022 DOI: 10.3847/1538-4357/ac7aa2 Preferential Heating of Protons over Electrons from Coherent Structures during the First Perihelion of the Parker Solar Probe The solar wind undergoes significant heating as it propagates away from the Sun; the exact mechanisms responsible for this heating remain unclear. Using data from the first perihelion of the Parker Solar Probe mission, we examine the properties of proton and electron heating occurring within magnetic coherent structures identified by means of the Partial Variance of Increments (PVI) method. Statistically, regions of space with strong gradients in the magnetic field, PVI \ensuremath\geq 1, are associated with strongly enhance ... Sioulas, Nikos; Shi, Chen; Huang, Zesen; Velli, Marco; Published by: \apjl Published on: aug YEAR: 2022 DOI: 10.3847/2041-8213/ac85de Linking Small-scale Solar Wind Properties with Large-scale Coronal Source Regions through Joint Parker Solar Probe-Metis/Solar Orbiter Observations The solar wind measured in situ by Parker Solar Probe in the very inner heliosphere is studied in combination with the remote-sensing observation of the coronal source region provided by the METIS coronagraph aboard Solar Orbiter. The coronal outflows observed near the ecliptic by Metis on 2021 January 17 at 16:30 UT, between 3.5 and 6.3 R$_\ensuremath\odot$above the eastern solar limb, can be associated with the streams sampled by PSP at 0.11 and 0.26 au from the Sun, in two time intervals almost 5 days apart. The two pla ... Telloni, Daniele; Zank, Gary; Sorriso-Valvo, Luca; Amicis, Raffaella; Panasenco, Olga; Susino, Roberto; Bruno, Roberto; Perrone, Denise; Adhikari, Laxman; Liang, Haoming; Nakanotani, Masaru; Zhao, Lingling; Hadid, Lina; anchez-Cano, Beatriz; Verscharen, Daniel; Velli, Marco; Grimani, Catia; Marino, Raffaele; Carbone, Francesco; Mancuso, Salvatore; Biondo, Ruggero; Pagano, Paolo; Reale, Fabio; Bale, Stuart; Kasper, Justin; Case, Anthony; de Wit, Thierry; Goetz, Keith; Harvey, Peter; Korreck, Kelly; Larson, Davin; Livi, Roberto; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Stevens, Michael; Whittlesey, Phyllis; Romoli, Marco; Andretta, Vincenzo; Da Deppo, Vania; Fineschi, Silvano; Heinzel, Petr; Moses, John; Naletto, Giampiero; Nicolini, Gianalfredo; Spadaro, Daniele; Stangalini, Marco; Teriaca, Luca; Capobianco, Gerardo; Capuano, Giuseppe; Casini, Chiara; Casti, Marta; Chioetto, Paolo; Corso, Alain; De Leo, Yara; Fabi, Michele; Frassati, Federica; Frassetto, Fabio; Giordano, Silvio; Guglielmino, Salvo; Jerse, Giovanna; Landini, Federico; Liberatore, Alessandro; Magli, Enrico; Massone, Giuseppe; Messerotti, Mauro; Pancrazzi, Maurizio; Pelizzo, Maria; Romano, Paolo; Sasso, Clementina; Schühle, Udo; Slemer, Alessandra; Straus, Thomas; Uslenghi, Michela; Volpicelli, Cosimo; Zangrilli, Luca; Zuppella, Paola; Abbo, Lucia; Auchère, Fr\; Cuadrado, Regina; Berlicki, Arkadiusz; Ciaravella, Angela; Lamy, Philippe; Lanzafame, Alessandro; Malvezzi, Marco; Nicolosi, Piergiorgio; o, Giuseppe; Peter, Hardi; Solanki, Sami; Strachan, Leonard; Tsinganos, Kanaris; Ventura, Rita; Vial, Jean-Claude; Woch, Joachim; Zimbardo, Gaetano; Published by: \apj Published on: aug YEAR: 2022 DOI: 10.3847/1538-4357/ac8103 Turbulence and Waves in the Sub-Alfv\ enic Solar Wind Observed by the Parker Solar Probe during Encounter 10 During its 10th orbit around the Sun, the Parker Solar Probe sampled two intervals where the local Alfv\ en speed exceeded the solar wind speed, lasting more than 10 hours in total. In this paper, we analyze the turbulence and wave properties during these periods. The turbulence is observed to be Alfv\ enic and unbalanced, dominated by outward-propagating modes. The power spectrum of the outward-propagating Elsässer z$^+$mode steepens at high frequencies while that of the inward- propagating z$^-$mode flattens. The obse ... Zhao, L.; Zank, G.~P.; Adhikari, L.; Telloni, D.; Stevens, M.; Kasper, J.~C.; Bale, S.~D.; Raouafi, N.~E.; Published by: \apjl Published on: aug YEAR: 2022 DOI: 10.3847/2041-8213/ac8353 Patches of Magnetic Switchbacks and Their Origins Parker Solar Probe (PSP) has shown that the solar wind in the inner heliosphere is characterized by the quasi omnipresence of magnetic switchbacks ( switchback hereinafter), local backward bends of magnetic field lines. Switchbacks also tend to come in patches, with a large-scale modulation that appears to have a spatial scale size comparable to supergranulation on the Sun. Here we inspect data from the first 10 encounters of PSP focusing on different time intervals when clear switchback patches were observed by PSP. We s ... Shi, Chen; Panasenco, Olga; Velli, Marco; Tenerani, Anna; Verniero, Jaye; Sioulas, Nikos; Huang, Zesen; Brosius, A.; Bale, Stuart; Klein, Kristopher; Kasper, Justin; de Wit, Thierry; Goetz, Keith; Harvey, Peter; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Larson, Davin; Livi, Roberto; Case, Anthony; Stevens, Michael; Published by: \apj Published on: aug YEAR: 2022 DOI: 10.3847/1538-4357/ac7c11 The Turbulent Properties of the Sub-Alfv\ enic Solar Wind Measured by the Parker Solar Probe For the first time, Parker Solar Probe (PSP) observed the sub- Alfv\ enic solar wind where the solar wind bulk speed drops below the local Alfv\ en speed for an extended period of time. Here, we report on the turbulent properties of the sub- Alfv\ enic region. We analyze the turbulence correlation length and the energy transfer and compare the results with nearby super-Alfv\ enic regions. As the Alfv\ en speed is larger or comparable to the solar wind speed in the intervals studied, we use a modified Taylor s hypothesis to a ... Zhao, L.; Zank, G.~P.; Telloni, D.; Stevens, M.; Kasper, J.~C.; Bale, S.~D.; Published by: \apjl Published on: apr YEAR: 2022 DOI: 10.3847/2041-8213/ac5fb0 Magnetic Switchback Occurrence Rates in the Inner Heliosphere: Parker Solar Probe and 1 au The subject of switchbacks, defined either as large angular deflections or polarity reversals of the magnetic field, has generated substantial interest in the space physics community since the launch of the Parker Solar Probe (PSP) in 2018. Previous studies have characterized switchbacks in several different ways and have been restricted to data available from the first few orbits. Here, we analyze the frequency of occurrence of switchbacks per unit distance for the first full eight orbits of PSP. In this work, events that r ... Pecora, Francesco; Matthaeus, William; Primavera, Leonardo; Greco, Antonella; Chhiber, Rohit; Bandyopadhyay, Riddhi; Servidio, Sergio; Published by: \apjl Published on: apr YEAR: 2022 DOI: 10.3847/2041-8213/ac62d4 Markovian Features of the Solar Wind at Subproton Scales The interplanetary magnetic field carried out from the Sun by the solar wind displays fluctuations over a wide range of scales. While at large scales, say at frequencies lower than 0.1-1 Hz, fluctuations display the universal character of fully developed turbulence with a well-defined Kolmogorov-like inertial range, the physical and dynamical properties of the small-scale regime as well as their connection with the large-scale ones are still a debated topic. In this work we investigate the near-Sun magnetic field fluctuation ... Benella, Simone; Stumpo, Mirko; Consolini, Giuseppe; Alberti, Tommaso; Carbone, Vincenzo; Laurenza, Monica; Published by: \apjl Published on: apr YEAR: 2022 DOI: 10.3847/2041-8213/ac6107 On the Conservation of Turbulence Energy in Turbulence Transport Models Zank et al. developed models describing the transport of low-frequency incompressible and nearly incompressible turbulence in inhomogeneous flows. The formalism was based on expressing the fluctuating variables in terms of the Elsässar variables and then taking moments subject to various closure hypotheses. The turbulence transport models are different according to whether the plasma beta regime is large, of order unity, or small. Here, we show explicitly that the three sets of turbulence transport models admit a conser ... Wang, B.; Zank, G.~P.; Adhikari, L.; Zhao, L.; Published by: \apj Published on: apr YEAR: 2022 DOI: 10.3847/1538-4357/ac596e Anisotropy of Magnetic Field Spectra at Kinetic Scales of Solar Wind Turbulence as Revealed by the Parker Solar Probe in the Inner Heliosphere Using the Parker Solar Probe data taken in the inner heliosphere, we investigate the power and spatial anisotropy of magnetic field spectra at kinetic scales (i.e., around sub-ion scales) in solar wind turbulence in the inner heliosphere. We find that strong anisotropy of the magnetic spectra occurs at kinetic scales with the strongest power in the perpendicular direction with respect to the local magnetic field (forming an angle \ensuremath\theta$_B$with the mean flow velocity). The spectral index of the magnetic spectra ... Huang, S.~Y.; Xu, S.~B.; Zhang, J.; Sahraoui, F.; es, Andr\; He, J.~S.; Yuan, Z.~G.; Deng, X.~H.; Jiang, K.; Wei, Y.~Y.; Xiong, Q.~Y.; Wang, Z.; Yu, L.; Lin, R.~T.; Published by: \apjl Published on: apr YEAR: 2022 DOI: 10.3847/2041-8213/ac5f02 Kinetic-scale Current Sheets in Near-Sun Solar Wind: Properties, Scale-dependent Features and Reconnection Onset We present statistical analysis of 11,200 proton kinetic-scale current sheets (CS) observed by the Parker Solar Probe during 10 days around the first perihelion. The CS thickness {\ensuremath{\lambda}} is in the range from a few to 200 km with the typical value around 30 km, while current densities are in the range from 0.1 to 10 {\ensuremath{\mu}}A m$^{-2}$with the typical value around 0.7 {\ensuremath{\mu}}A m$^{-2}$. These CSs are resolved thanks to magnetic field measurements at 73-290 samples s$^{-1}\$ resolution. In te ... Lotekar, A.~B.; Vasko, I.~Y.; Phan, T.; Bale, S.~D.; Bowen, T.~A.; Halekas, J.; Artemyev, A.~V.; Khotyaintsev, Yu.; Mozer, F.~S.; Published by: \apj      Published on: apr YEAR: 2022     DOI: 10.3847/1538-4357/ac5bd9 2021 Exploring the Solar Wind from Its Source on the Corona into the Inner Heliosphere during the First Solar Orbiter-Parker Solar Probe Quadrature This Letter addresses the first Solar Orbiter (SO)-Parker Solar Probe (PSP) quadrature, occurring on 2021 January 18 to investigate the evolution of solar wind from the extended corona to the inner heliosphere. Assuming ballistic propagation, the same plasma volume observed remotely in the corona at altitudes between 3.5 and 6.3 solar radii above the solar limb with the Metis coronagraph on SO can be tracked to PSP, orbiting at 0.1 au, thus allowing the local properties of the solar wind to be linked to the coronal source re ... Telloni, Daniele; Andretta, Vincenzo; Antonucci, Ester; Bemporad, Alessandro; Capuano, Giuseppe; Fineschi, Silvano; Giordano, Silvio; Habbal, Shadia; Perrone, Denise; Pinto, Rui; Sorriso-Valvo, Luca; Spadaro, Daniele; Susino, Roberto; Woodham, Lloyd; Zank, Gary; Romoli, Marco; Bale, Stuart; Kasper, Justin; Auchère, Fr\; Bruno, Roberto; Capobianco, Gerardo; Case, Anthony; Casini, Chiara; Casti, Marta; Chioetto, Paolo; Corso, Alain; Da Deppo, Vania; De Leo, Yara; de Wit, Thierry; Frassati, Federica; Frassetto, Fabio; Goetz, Keith; Guglielmino, Salvo; Harvey, Peter; Heinzel, Petr; Jerse, Giovanna; Korreck, Kelly; Landini, Federico; Larson, Davin; Liberatore, Alessandro; Livi, Roberto; MacDowall, Robert; Magli, Enrico; Malaspina, David; Massone, Giuseppe; Messerotti, Mauro; Moses, John; Naletto, Giampiero; Nicolini, Gianalfredo; o, Giuseppe; Panasenco, Olga; Pancrazzi, Maurizio; Pelizzo, Maria; Pulupa, Marc; Reale, Fabio; Romano, Paolo; Sasso, Clementina; Schühle, Udo; Stangalini, Marco; Stevens, Michael; Strachan, Leonard; Straus, Thomas; Teriaca, Luca; Uslenghi, Michela; Velli, Marco; Verscharen, Daniel; Volpicelli, Cosimo; Whittlesey, Phyllis; Zangrilli, Luca; Zimbardo, Gaetano; Zuppella, Paola; Published by: \apjl      Published on: oct YEAR: 2021     DOI: 10.3847/2041-8213/ac282f Evolution of Switchbacks in the Inner Heliosphere We analyze magnetic field data from the first six encounters of Parker Solar Probe, three Helios fast streams and two Ulysses south polar passes covering heliocentric distances 0.1 \ensuremath\lesssim R \ensuremath\lesssim 3 au. We use this data set to statistically determine the evolution of switchbacks of different periods and amplitudes with distance from the Sun. We compare the radial evolution of magnetic field variances with that of the mean square amplitudes of switchbacks, and quantify the radial evolution of the cum ... Tenerani, Anna; Sioulas, Nikos; Matteini, Lorenzo; Panasenco, Olga; Shi, Chen; Velli, Marco; Published by: \apjl      Published on: oct YEAR: 2021     DOI: 10.3847/2041-8213/ac2606 Impact of Switchbacks on Turbulent Cascade and Energy Transfer Rate in the Inner Heliosphere Recent Parker Solar Probe (PSP) observations of inner heliospheric plasma have shown an abundant presence of Alfv\ enic polarity reversal of the magnetic field, known as switchbacks. While their origin is still debated, their role in driving the solar wind turbulence has been suggested through analysis of the spectral properties of magnetic fluctuations. Here, we provide a complementary assessment of their role in the turbulent cascade. The validation of the third-order linear scaling of velocity and magnetic fluctuation ... andez, Carlos; Sorriso-Valvo, Luca; Bandyopadhyay, Riddhi; Chasapis, Alexandros; asconez, Christian; Marino, Raffaele; Pezzi, Oreste; Published by: \apjl      Published on: nov YEAR: 2021     DOI: 10.3847/2041-8213/ac36d1 Small-scale Magnetic Flux Ropes with Field-aligned Flows via the PSP In Situ Observations Magnetic flux rope, formed by the helical magnetic field lines, can sometimes maintain its shape while carrying significant plasma flow that is aligned with the local magnetic field. We report the existence of such structures and static flux ropes by applying the Grad-Shafranov-based algorithm to the Parker Solar Probe in situ measurements in the first five encounters. These structures are detected at heliocentric distances, ranging from 0.13 to 0.66 au, in a 4-month time period. We find that flux ropes with field-aligned fl ... Chen, Yu; Hu, Qiang; Zhao, Lingling; Kasper, Justin; Huang, Jia; Published by: \apj      Published on: jun YEAR: 2021     DOI: 10.3847/1538-4357/abfd30 Anisotropy of Solar Wind Turbulence in the Inner Heliosphere at Kinetic Scales: PSP Observations The anisotropy of solar wind turbulence is a critical issue in understanding the physics of energy transfer between scales and energy conversion between fields and particles in the heliosphere. Using the measurement of Parker Solar Probe (PSP), we present an observation of the anisotropy at kinetic scales in the slow, Alfv\ enic, solar wind in the inner heliosphere. The magnetic compressibility behaves as expected for kinetic Alfv\ enic turbulence below the ion scale. A steepened transition range is found between the inertia ... Duan, Die; He, Jiansen; Bowen, Trevor; Woodham, Lloyd; Wang, Tieyan; Chen, Christopher; Mallet, Alfred; Bale, Stuart; Published by: \apjl      Published on: jul YEAR: 2021     DOI: 10.3847/2041-8213/ac07ac General Exact Law of Compressible Isentropic Magnetohydrodynamic Flows: Theory and Spacecraft Observations in the Solar Wind 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 ... Simon, P.; Sahraoui, F.; Published by: \apj      Published on: jul YEAR: 2021     DOI: 10.3847/1538-4357/ac0337 Turbulent Generation of Magnetic Switchbacks in the Alfv\ enic Solar Wind One of the most important early results from the Parker Solar Probe (PSP) is the ubiquitous presence of magnetic switchbacks, whose origin is under debate. Using a three-dimensional direct numerical simulation of the equations of compressible magnetohydrodynamics from the corona to 40 solar radii, we investigate whether magnetic switchbacks emerge from granulation-driven Alfv\ en waves and turbulence in the solar wind. The simulated solar wind is an Alfv\ enic slow-solar- wind stream with a radial profile consistent with var ... Shoda, Munehito; Chandran, Benjamin; Cranmer, Steven; Published by: \apj      Published on: jul YEAR: 2021     DOI: 10.3847/1538-4357/abfdbc Analysis of Magnetohydrodynamic Perturbations in the Radial-field Solar Wind from Parker Solar Probe Observations We report analysis of sub-Alfv\ enic magnetohydrodynamic (MHD) perturbations in the low-\ensuremath\beta radial-field solar wind employing the Parker Solar Probe spacecraft data from 2018 October 31 to November 12. We calculate wavevectors using the singular value decomposition method and separate MHD perturbations into three eigenmodes (Alfv\ en, fast, and slow modes) to explore the properties of sub-Alfv\ enic perturbations and the role of compressible perturbations in solar wind heating. The MHD perturbations show a high ... Zhao, S.~Q.; Yan, Huirong; Liu, Terry; Liu, Mingzhe; Shi, Mijie; Published by: \apj      Published on: dec YEAR: 2021     DOI: 10.3847/1538-4357/ac2ffe Domains of Magnetic Pressure Balance in Parker Solar Probe Observations of the Solar Wind The Parker Solar Probe (PSP) spacecraft is performing the first in situ exploration of the solar wind within 0.2 au of the Sun. Initial observations confirmed the Alfv\ enic nature of aligned fluctuations of the magnetic field B and velocity V in solar wind plasma close to the Sun, in domains of nearly constant magnetic field magnitude \ensuremath\mid B \ensuremath\mid, i.e., approximate magnetic pressure balance. Such domains are interrupted by particularly strong fluctuations, including but not limited to radial field (pol ... Ruffolo, David; Ngampoopun, Nawin; Bhora, Yash; Thepthong, Panisara; Pongkitiwanichakul, Peera; Matthaeus, William; Chhiber, Rohit; Published by: \apj      Published on: dec YEAR: 2021     DOI: 10.3847/1538-4357/ac2ee3 Large-scale Structure and Turbulence Transport in the Inner Solar Wind: Comparison of Parker Solar Probe s First Five Orbits with a Global 3D Reynolds-averaged MHD Model Simulation results from a global magnetohydrodynamic model of the solar corona and solar wind are compared with Parker Solar Probe (PSP) observations during its first five orbits. The fully three- dimensional model is based on Reynolds-averaged mean-flow equations coupled with turbulence-transport equations. The model includes the effects of electron heat conduction, Coulomb collisions, turbulent Reynolds stresses, and heating of protons and electrons via a turbulent cascade. Turbulence-transport equations for average turbul ... Chhiber, Rohit; Usmanov, Arcadi; Matthaeus, William; Goldstein, Melvyn; Published by: \apj      Published on: dec YEAR: 2021     DOI: 10.3847/1538-4357/ac1ac7 MHD and Ion Kinetic Waves in Field-aligned Flows Observed by Parker Solar Probe Parker Solar Probe (PSP) observed predominately Alfv\ enic fluctuations in the solar wind near the Sun where the magnetic field tends to be radially aligned. In this paper, two magnetic- field-aligned solar wind flow intervals during PSP s first two orbits are analyzed. Observations of these intervals indicate strong signatures of parallel/antiparallel-propagating waves. We utilize multiple analysis techniques to extract the properties of the observed waves in both magnetohydrodynamic (MHD) and kinetic scales. At the MHD sca ... Zhao, L.; Zank, G.~P.; He, J.~S.; Telloni, D.; Adhikari, L.; Nakanotani, M.; Kasper, J.~C.; Bale, S.~D.; Published by: \apj      Published on: dec YEAR: 2021     DOI: 10.3847/1538-4357/ac28fb

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