# PSP Bibliography

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## Found 200 entries in the Bibliography.

### Showing entries from 1 through 50

 2021 Nonlinear Wave-Wave Coupling Related to Whistler-mode and Electron Bernstein Waves Observed by the Parker Solar Probe We report nonlinear wave-wave coupling related to whistler-mode or electron Bernstein waves in the near-Sun slow solar wind with Parker Solar Probe (PSP) data. Prominent plasma wave power enhancements usually exist near the electron gyrofrequency (f$_ce$), identified as electrostatic whistler-mode and electron Bernstein waves (Malaspina et al. 2020). We find that these plasma waves near f$_ce$ typically have a harmonic spectral structure and further classify them into three types identified by the characteristics of wave fre ... Ma, Jiuqi; Gao, Xinliang; Yang, Zhongwei; Tsurutani, Bruce; Liu, Mingzhe; Lu, Quanming; Wang, Shui; Published by: \apj      Published on: sep YEAR: 2021     DOI: 10.3847/1538-4357/ac0ef4 BepiColombo s cruise phase: unique opportunity for synergistic observations The investigation of multi-spacecraft coordinated observations during the cruise phase of BepiColombo (ESA/JAXA) are reported, with a particular emphasis on the recently launched missions, Solar Orbiter (ESA/NASA) and Parker Solar Probe (NASA). Despite some payload constraints, many instruments onboard BepiColombo are operating during its cruise phase simultaneously covering a wide range of heliocentric distances [0.28 AU - 0.5 AU]. Hence, the various spacecraft configurations and the combined in-situ and remote sensing meas ... Hadid, L.~Z.; enot, V.; Aizawa, S.; Milillo, A.; Zender, J.; Murakami, G.; Benkhoff, J.; Zouganelis, I.; Alberti, T.; e, Andr\; Bebesi, Z.; Califano, F.; Dimmock, A.~P.; Dosa, M.; Escoubet, C.~P.; Griton, L.; Ho, G.~C.; Horbury, T.~S.; Iwai, K.; Janvier, M.; Kilpua, E.; Lavraud, B.; Madar, A.; Miyoshi, Y.; Müller, D.; Pinto, R.~F.; Rouillard, A.~P.; Raines, J.~M.; Raouafi, N.; Sahraoui, F.; anchez-Cano, B.; Shiota, D.; Vainio, R.; Walsh, A.; Published by: Frontiers in Astronomy and Space Sciences      Published on: sep YEAR: 2021     DOI: 10.3389/fspas.2021.718024 Triggered Ion-acoustic Waves in the Solar Wind For more than 12 hr beginning on 2021 January 18, continuous narrowband electrostatic emissions were observed on the Parker Solar Probe near 20 solar radii. The observed <1000 Hz frequencies were well below the local ion-plasma frequency. Surprisingly, the emissions consisted of electrostatic wave packets with shock- like envelopes, appearing repetitively at a \raisebox-0.5ex\textasciitilde1.5 Hz rate. This repetitiveness correlated and was in phase with low-frequency electromagnetic fluctuations. The emissions were associat ... Mozer, F.~S.; Vasko, I.~Y.; Verniero, J.~L.; Published by: \apjl      Published on: sep YEAR: 2021     DOI: 10.3847/2041-8213/ac2259 On the Origin of Switchbacks Observed in the Solar Wind The origin of switchbacks in the solar wind is discussed in two classes of theory that differ in the location of the source being either near the transition region near the Sun or in the solar wind itself. The two classes of theory differ in their predictions of the switchback rate (the number of switchbacks observed per hour) as a function of distance from the Sun. To distinguish between these theories, one-hour averages of Parker Solar Probe data were averaged over five orbits to find the following: (1) The hourly averaged ... Mozer, F.~S.; Bale, S.~D.; Bonnell, J.~W.; Drake, J.~F.; Hanson, E.~L.~M.; Mozer, M.~C.; Published by: \apj      Published on: sep YEAR: 2021     DOI: 10.3847/1538-4357/ac110d On the Role of Solar Wind Expansion as a Source of Whistler Waves: Scattering of Suprathermal Electrons and Heat Flux Regulation in the Inner Heliosphere The role of solar wind expansion in generating whistler waves is investigated using the EB-iPic3D code, which models solar wind expansion self-consistently within a fully kinetic semi-implicit approach. The simulation is initialized with an electron velocity distribution function modeled after observations of the Parker Solar Probe during its first perihelion at 0.166 au, consisting of a dense core and an antisunward strahl. This distribution function is initially stable with respect to kinetic instabilities. Expansion drive ... Micera, A.; Zhukov, A.~N.; opez, R.~A.; Boella, E.; Tenerani, A.; Velli, M.; Lapenta, G.; Innocenti, M.~E.; Published by: \apj      Published on: sep YEAR: 2021     DOI: 10.3847/1538-4357/ac1067 The Evolution of Compressible Solar Wind Turbulence in the Inner Heliosphere: PSP, THEMIS, and MAVEN Observations The first computations of the compressible energy transfer rate from \raisebox-0.5ex\textasciitilde0.2 up to \raisebox-0.5ex\textasciitilde1.7 au is obtained using Parker Solar Probe (PSP), Time History of Events and Macroscale Interactions during Substorms (THEMIS), and Mars Atmosphere and Volatile EvolutioN (MAVEN) observations. Using a recently derived exact relation for isothermal magnetohydrodynamics turbulence, the compressible energy cascade rate, \ensuremath\varepsilon$_C$, is computed for hundred of events at differ ... es, Andr\; Sahraoui, F.; Hadid, L.~Z.; Huang, S.~Y.; Romanelli, N.; Galtier, S.; DiBraccio, G.; Halekas, J.; Published by: \apj      Published on: sep YEAR: 2021     DOI: 10.3847/1538-4357/ac0af5 Evolution of Large-amplitude Alfv\ en Waves and Generation of Switchbacks in the Expanding Solar Wind Motivated by recent Parker Solar Probe (PSP) observations of switchbacks (abrupt, large-amplitude reversals in the radial magnetic field, which exhibit Alfv\ enic correlations), we examine the dynamics of large-amplitude Alfv\ en waves in the expanding solar wind. We develop an analytic model that makes several predictions: switchbacks should preferentially occur in regions where the solar wind plasma has undergone a greater expansion, the switchback fraction at radii comparable to PSP should be an increasing function of ... Mallet, Alfred; Squire, Jonathan; Chandran, Benjamin; Bowen, Trevor; Bale, Stuart; Published by: \apj      Published on: sep YEAR: 2021     DOI: 10.3847/1538-4357/ac0c12 Solar wind rotation rate and shear at coronal hole boundaries. Possible consequences for magnetic field inversions Context. In situ measurements by several spacecraft have revealed that the solar wind is frequently perturbed by transient structures that have been interpreted as magnetic folds, jets, waves, and flux ropes that propagate rapidly away from the Sun over a large range of heliocentric distances. Parker Solar Probe (PSP), in particular, has detected very frequent rotations of the magnetic field vector at small heliocentric radial distances, accompanied by surprisingly large solar wind rotation rates. The physical origin of such ... Pinto, R.~F.; Poirier, N.; Rouillard, A.~P.; Kouloumvakos, A.; Griton, L.; Fargette, N.; Kieokaew, R.; Lavraud, B.; Brun, A.~S.; Published by: \aap      Published on: sep YEAR: 2021     DOI: 10.1051/0004-6361/202040180 Characteristic Scales of Magnetic Switchback Patches Near the Sun and Their Possible Association With Solar Supergranulation and Granulation 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 Origin of Compressive Alfv\ enic Spikes/Kinks as Observed by Parker Solar Probe The solar wind is found by the Parker Solar Probe to be abundant with Alfv\ enic velocity spikes and magnetic field kinks. Temperature enhancement is another remarkable feature associated with the Alfv\ enic spikes. How the prototype of these coincident phenomena is generated intermittently in the source region is an important and wide-ranging subject. Here we propose a new model introducing guide-field discontinuity into the interchange magnetic reconnection between open funnels and closed loops with different magnetic heli ... He, Jiansen; Zhu, Xingyu; Yang, Liping; Hou, Chuanpeng; Duan, Die; Zhang, Lei; Wang, Ying; Published by: \apjl      Published on: may YEAR: 2021     DOI: 10.3847/2041-8213/abf83d Measurement of the open magnetic flux in the inner heliosphere down to 0.13 AU Context. Robustly interpreting sets of in situ spacecraft data of the heliospheric magnetic field (HMF) for the purpose of probing the total unsigned magnetic flux in the heliosphere is critical for constraining global coronal models as well as understanding the large scale structure of the heliosphere itself. The heliospheric flux (\ensuremath\Phi$_H$) is expected to be a spatially conserved quantity with a possible secular dependence on the solar cycle and equal to the measured radial component of the HMF weighted by the s ... Badman, Samuel; Bale, Stuart; Rouillard, Alexis; Bowen, Trevor; Bonnell, John; Goetz, Keith; Harvey, Peter; MacDowall, Robert; Malaspina, David; Pulupa, Marc; Published by: \aap      Published on: jun YEAR: 2021     DOI: 10.1051/0004-6361/202039407 The Electron Structure of the Solar Wind Time-series measurements of the number density ncore and temperature Tcore of the core-electron population of the solar wind are examined at 1 AU and at 0.13 AU using measurements from the WIND and Parker Solar Probe spacecraft, respectively. A statistical analysis of the ncore and Tcore measurements at 1 AU finds that the core-electron spatial structure of the solar wind is related to the magnetic-flux-tube structure of the solar wind; this electron structure is characterized by jumps in the values of ncore and Tcore when p ... Borovsky, Joseph; Halekas, Jasper; Whittlesey, Phyllis; Published by: Frontiers in Astronomy and Space Sciences      Published on: jun YEAR: 2021     DOI: 10.3389/fspas.2021.690005 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 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 Energetic particle evolution during coronal mass ejection passage from 0.3 to 1 AU We provide analysis of a coronal mass ejection (CME) that passed over Parker Solar Probe (PSP) on January 20, 2020 when the spacecraft was at just 0.32 AU. The Integrated Science Investigation of the Sun instrument suite measures energetic particle populations associated with the CME before, during, and after its passage over the spacecraft. We observe a complex evolution of energetic particles, including a brief \raisebox-0.5ex\textasciitilde2 h period where the energetic particle fluxes are enhanced and the nominal orienta ... Joyce, C.~J.; McComas, D.~J.; Schwadron, N.~A.; Vourlidas, A.; Christian, E.~R.; McNutt, R.~L.; Cohen, C.~M.~S.; Leske, R.~A.; Mewaldt, R.~A.; Stone, E.~C.; Mitchell, D.~G.; Hill, M.~E.; Roelof, E.~C.; Allen, R.~C.; Szalay, J.~R.; Rankin, J.~S.; Desai, M.~I.; Giacalone, J.; Matthaeus, W.~H.; Niehof, J.~T.; de Wet, W.; Winslow, R.~M.; Bale, S.~D.; Kasper, J.~C.; Published by: \aap      Published on: jul YEAR: 2021     DOI: 10.1051/0004-6361/202039933 Flux conservation, radial scalings, Mach numbers, and critical distances in the solar wind: magnetohydrodynamics and Ulysses observations One of the key challenges in solar and heliospheric physics is to understand the acceleration of the solar wind. As a super-sonic, super-Alfv\ enic plasma flow, the solar wind carries mass, momentum, energy, and angular momentum from the Sun into interplanetary space. We present a framework based on two-fluid magnetohydrodynamics to estimate the flux of these quantities based on spacecraft data independent of the heliocentric distance of the location of measurement. Applying this method to the Ulysses dataset allows us to st ... Verscharen, Daniel; Bale, Stuart; Velli, Marco; Published by: \mnras      Published on: jul YEAR: 2021     DOI: 10.1093/mnras/stab2051 The Sunward Electron Deficit: A Telltale Sign of the Sun s Electric Potential As the Parker Solar Probe explores new regions of the inner heliosphere, it travels ever deeper into the electric potential of the Sun. In the near-Sun environment, a new feature of the electron distribution emerges, in the form of a deficit in the sunward suprathermal population. The lower boundary of this deficit forms a cutoff in phase space, at an energy determined by the electric potential drop between the observation point and the outer heliosphere. We explore the characteristics of the sunward deficit and the associat ... Halekas, J.~S.; Ber\vci\vc, L.; Whittlesey, P.; Larson, D.~E.; Livi, R.; Berthomier, M.; Kasper, J.~C.; Case, A.~W.; Stevens, M.~L.; Bale, S.~D.; MacDowall, R.~J.; Pulupa, M.~P.; Published by: \apj      Published on: jul YEAR: 2021     DOI: 10.3847/1538-4357/ac096e 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 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 Characteristics of Interplanetary Discontinuities in the Inner Heliosphere Revealed by Parker Solar Probe We present a statistical analysis for the characteristics and spatial evolution of the interplanetary discontinuities (IDs) in the solar wind, from 0.13-0.9 au, by using the Parker Solar Probe measurements on Orbits 4 and 5. We collected 3948 IDs, including 2511 rotational discontinuities (RDs) and 557 tangential discontinuities (TDs), with the remnant unidentified. The statistical results show that (1) the ID occurrence rate decreases from 200 events per day at 0.13 au to 1 event per day at 0.9 au, following a spatial scali ... Liu, Y.~Y.; Fu, H.~S.; Cao, J.~B.; Liu, C.~M.; Wang, Z.; Guo, Z.~Z.; Xu, Y.; Bale, S.~D.; Kasper, J.~C.; Published by: \apj      Published on: aug YEAR: 2021     DOI: 10.3847/1538-4357/ac06a1 Multi-spacecraft study of the solar wind at solar minimum: Dependence on latitude and transient outflows Context. The recent launches of Parker Solar Probe, Solar Orbiter (SO), and BepiColombo, along with several older spacecraft, have provided the opportunity to study the solar wind at multiple latitudes and distances from the Sun simultaneously. \ Aims: We take advantage of this unique spacecraft constellation, along with low solar activity across two solar rotations between May and July 2020, to investigate how the solar wind structure, including the heliospheric current sheet (HCS), varies with latitude. \ Methods: We visua ... Laker, R.; Horbury, T.~S.; Bale, S.~D.; Matteini, L.; Woolley, T.; Woodham, L.~D.; Stawarz, J.~E.; Davies, E.~E.; Eastwood, J.~P.; Owens, M.~J.; Brien, H.; Evans, V.; Angelini, V.; Richter, I.; Heyner, D.; Owen, C.~J.; Louarn, P.; Fedorov, A.; Published by: \aap      Published on: aug YEAR: 2021     DOI: 10.1051/0004-6361/202140679 Plasma Properties, Switchback Patches and Low \ensuremath\alpha-Particle Abundance in Slow Alfv\ enic Coronal Hole Wind at 0.13 au The Parker Solar Probe (PSP) mission presents a unique opportunity to study the near-Sun solar wind closer than any previous spacecraft. During its fourth and fifth solar encounters, PSP had the same orbital trajectory, meaning that solar wind was measured at the same latitudes and radial distances. We identify two streams measured at the same heliocentric distance (\raisebox-0.5ex\textasciitilde0.13au) and latitude (\raisebox-0.5ex\textasciitilde-3.5$^○$) across these encounters to reduce spatial evolution effects. By com ... Woolley, Thomas; Matteini, Lorenzo; McManus, Michael; Ber\vci\vc, Laura; Badman, Samuel; Woodham, Lloyd; Horbury, Timothy; Bale, Stuart; Laker, Ronan; Stawarz, Julia; Larson, Davin; Published by: \mnras      Published on: aug YEAR: 2021     DOI: 10.1093/mnras/stab2281 Assessing the Role of Interchange Reconnection in Forming Switchbacks Abrupt deflections of the magnetic field in the solar wind, so called switchbacks, are frequently observed by the Parker Solar Probe (PSP) during its first two orbits and are believed to play an important role in unveiling the nature of solar corona heating and solar wind acceleration in the inner heliosphere. Many attempts were made recently to understand the nature of switchbacks. However, the origin, propagation, and evolution of switchbacks are still under debate. In this study, we attempt to use the linear theory of ... Liang, H.; Zank, G.~P.; Nakanotani, M.; Zhao, L.; Published by: \apj      Published on: aug YEAR: 2021     DOI: 10.3847/1538-4357/ac0a73 Evolution of Interplanetary Coronal Mass Ejection Complexity: A Numerical Study through a Swarm of Simulated Spacecraft In-situ measurements carried out by spacecraft in radial alignment are critical to advance our knowledge on the evolutionary behavior of coronal mass ejections (CMEs) and their magnetic structures during propagation through interplanetary space. Yet, the scarcity of radially aligned CME crossings restricts investigations on the evolution of CME magnetic structures to a few case studies, preventing a comprehensive understanding of CME complexity changes during propagation. In this Letter, we perform numerical simulations of C ... Scolini, Camilla; Winslow, Reka; Lugaz, No\; Poedts, Stefaan; Published by: \apjl      Published on: aug YEAR: 2021     DOI: 10.3847/2041-8213/ac0d58 Dynamics of nanodust in the vicinity of a stellar corona: Effect of plasma corotation Context. In the vicinity of the Sun or other stars, the motion of the coronal and stellar wind plasma must include some amount of corotation, which could affect the dynamics of charged dust particles. In the case of the Sun, this region is now investigated in situ by the Parker Solar Probe. Charged dust particles coming from the vicinity of the Sun can also reach, and possibly be detected by, the Solar Orbiter. \ Aims: We use numerical simulations and theoretical models to study the effect of plasma corotation on the motion ... Czechowski, A.; Mann, I.; Published by: \aap      Published on: aug YEAR: 2021     DOI: 10.1051/0004-6361/202141048 Large Amplitude Switchback Turbulence: Possible Magnetic Velocity Alignment Structures Switchbacks are widely acknowledged phenomena observed by the Parker Solar Probe and appear to occur in patches. Previous studies focused on the fluctuations at the magnetic reversals. However, the nature of the fluctuations inside the switchbacks remains unknown. Here we utilize the magnetic field data and plasma data measured by the Parker Solar Probe in the first four encounters. We investigate the fluctuations in the switchback intervals of 100 s with $B_R 0$ at every instant and compare them to the fluctuations in the n ... Wu, Honghong; Tu, Chuanyi; Wang, Xin; Yang, Liping; Published by: The Astrophysical Journal      Published on: 06/2021 YEAR: 2021     DOI: 10.3847/1538-4357/abec6c A Focused Transport-based Kinetic Fractional Diffusion-advection Equation for Energetic Particle Trapping and Reconnection-related Acceleration by Small-scale Magnetic Flux Ropes in the Solar Wind Analysis of energetic particle inner heliospheric spacecraft data increasingly suggests the existence of anomalous diffusion phenomena that should be addressed to achieve a better understanding of energetic particle transport and acceleration in the expanding solar wind medium. Related to this is fast-growing observational evidence supporting the long-standing prediction from magnetohydrodynamic (MHD) theory and simulations of the presence of an inner heliospheric, dominant quasi-two-dimensional MHD turbulence component that ... le Roux, J.; Zank, G.; Published by: The Astrophysical Journal      Published on: 06/2021 YEAR: 2021     DOI: 10.3847/1538-4357/abf3c6 Time evolution of stream interaction region energetic particle spectra in the inner heliosphere We analyze an energetic proton event associated with a stream interaction region (SIR) that was observed at Parker Solar Probe on day 320 of 2018 when the spacecraft was just 0.34 AU from the Sun. Using the Integrated Science Investigation of the Sun instrument suite, we perform a spectral analysis of the event and show how the observed spectra evolve over the course of the event. We find that the spectra from the first day of the event are much more consistent with local acceleration at a weak compression, while spectra fro ... Joyce, C.; McComas, D.; Schwadron, N.; Christian, E.; Wiedenbeck, M.; McNutt, R.; Cohen, C.; Leske, R.; Mewaldt, R.; Stone, E.; Labrador, A.; Davis, A.; Cummings, A.; Mitchell, D.; Hill, M.; Roelof, E.; Allen, R.; Szalay, J.; Rankin, J.; Desai, M.; Giacalone, J.; Matthaeus, W.; Bale, S.; Kasper, J.; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202039330 Energetic particle behavior in near-Sun magnetic field switchbacks from PSP Context. The observation of numerous magnetic switchbacks and associated plasma jets in Parker Solar Probe (PSP) during its first five orbits, particularly near the Sun, has attracted considerable attention. Switchbacks have been found to be systematically associated with correlated reversals in the direction of the propagation of Alfvénic fluctuations, as well as similar reversals of the electron strahl. Aims: Here we aim to see whether the energetic particles change direction at the magnetic field switchbacks. Bandyopadhyay, R.; Matthaeus, W.; McComas, D.; Joyce, C.; Szalay, J.; Christian, E.; Giacalone, J.; Schwadron, N.; Mitchell, D.; Hill, M.; McNutt, R.; Desai, M.; Bale, S.; Bonnell, J.; de Wit, Dudok; Goetz, K.; Harvey, P.; MacDowall, R.; Malaspina, D.; Pulupa, M.; Kasper, J.; Stevens, M.; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202039800 Electron Bernstein waves and narrowband plasma waves near the electron cyclotron frequency in the near-Sun solar wind Context. Recent studies of the solar wind sunward of 0.25 AU reveal that it contains quiescent regions, with low-amplitude plasma and magnetic field fluctuations, and a magnetic field direction similar to the Parker spiral. The quiescent regions are thought to have a more direct magnetic connection to the solar corona than other types of solar wind, suggesting that waves or instabilities in the quiescent regions are indicative of the early evolution of the solar wind as it escapes the corona. The quiescent solar wind regions ... Malaspina, D.; Wilson, L.; Ergun, R.; Bale, S.; Bonnell, J.; Goodrich, K.; Goetz, K.; Harvey, P.; MacDowall, R.; Pulupa, M.; Halekas, J.; Case, A.; Kasper, J.; Larson, D.; Stevens, M.; Whittlesey, P.; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202140449 Applicability of Taylor s hypothesis during Parker Solar Probe perihelia We investigate the validity of Taylor s hypothesis (TH) in the analysis of velocity and magnetic field fluctuations in Alfvénic solar wind streams measured by Parker Solar Probe (PSP) during the first four encounters. The analysis is based on a recent model of the spacetime correlation of magnetohydrodynamic (MHD) turbulence, which has been validated in high-resolution numerical simulations of strong reduced MHD turbulence. We use PSP velocity and magnetic field measurements from 24 h intervals selected from each of the fir ... Perez, Jean; Bourouaine, Sofiane; Chen, Christopher; Raouafi, Nour; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202039879 The contribution of alpha particles to the solar wind angular momentum flux in the inner heliosphere Context. An accurate assessment of the Sun s angular momentum (AM) loss rate is an independent constraint for models that describe the rotation evolution of Sun-like stars. Aims: In situ measurements of the solar wind taken by Parker Solar Probe (PSP), at radial distances of ~28−55 R⊙, are used to constrain the solar wind AM-loss rate. For the first time with PSP, this includes a measurement of the alpha particle contribution. Methods: The mechanical AM flux in the solar wind protons (core and be ... Finley, A.; McManus, M.; Matt, S.; Kasper, J.; Korreck, K.; Case, A.; Stevens, M.; Whittlesey, P.; Larson, D.; Livi, R.; Bale, S.; de Wit, Dudok; Goetz, K.; Harvey, P.; MacDowall, R.; Malaspina, D.; Pulupa, M.; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202039288 Prevalence of magnetic reconnection in the near-Sun heliospheric current sheet During three of its first five orbits around the Sun, Parker Solar Probe (PSP) crossed the large-scale heliospheric current sheet (HCS) multiple times and provided unprecedented detailed plasma and field observations of the near-Sun HCS. We report the common detections by PSP of reconnection exhaust signatures in the HCS at heliocentric distances of 29.5-107 solar radii during encounters 1, 4, and 5. Both sunward and antisunward-directed reconnection exhausts were observed. In the sunward reconnection exhausts, PSP detected ... Phan, T.; Lavraud, B.; Halekas, J.; Øieroset, M.; Drake, J.; Eastwood, J.; Shay, M.; Pyakurel, P.; Bale, S.; Larson, D.; Livi, R.; Whittlesey, P.; Rahmati, A.; Pulupa, M.; McManus, M.; Verniero, J.; Bonnell, J.; Schwadron, N.; Stevens, M.; Case, A.; Kasper, J.; MacDowall, R.; Szabo, P.; Koval, A.; Korreck, K.; de Wit, Dudok; Malaspina, D.; Goetz, K.; Harvey, P.; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202039863 Detection of small magnetic flux ropes from the third and fourth Parker Solar Probe encounters Context. Aims: We systematically search for magnetic flux rope structures in the solar wind to within the closest distance to the Sun of ~0.13 AU, using data from the third and fourth orbits of the Parker Solar Probe. Methods: We extended our previous magnetic helicity-based technique of identifying magnetic flux rope structures. The method was improved upon to incorporate the azimuthal flow, which becomes larger as the spacecraft approaches the Sun. Results: A total of 21 and 34 magnetic flux ropes are ... Zhao, L.; Zank, G.; Hu, Q.; Telloni, D.; Chen, Y.; Adhikari, L.; Nakanotani, M.; Kasper, J.; Huang, J.; Bale, S.; Korreck, K.; Case, A.; Stevens, M.; Bonnell, J.; de Wit, Dudok; Goetz, K.; Harvey, P.; MacDowall, R.; Malaspina, D.; Pulupa, M.; Larson, D.; Livi, R.; Whittlesey, P.; Klein, K.; Raouafi, N.; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202039298 Wave-particle energy transfer directly observed in an ion cyclotron wave Context. The first studies with Parker Solar Probe (PSP) data have made significant progress toward understanding of the fundamental properties of ion cyclotron waves in the inner heliosphere. The survey mode particle measurements of PSP, however, did not make it possible to measure the coupling between electromagnetic fields and particles on the time scale of the wave periods. Aims: We present a novel approach to study wave-particle energy exchange with PSP. Methods: We used the Flux Angle operation mode of th ... Vech, D.; Martinovic, M.; Klein, K.; Malaspina, D.; Bowen, T.; Verniero, J.; Paulson, K.; de Wit, Dudok; Kasper, J.; Huang, J.; Stevens, M.; Case, A.; Korreck, K.; Mozer, F.; Goodrich, K.; Bale, S.; Whittlesey, P.; Livi, R.; Larson, D.; Pulupa, M.; Bonnell, J.; Harvey, P.; Goetz, K.; MacDowall, R.; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202039296 The active region source of a type III radio storm observed by Parker Solar Probe during encounter 2 Context. We investigated the source of a type III radio burst storm during encounter 2 of NASA s Parker Solar Probe (PSP) mission. Aims: It was observed that in encounter 2 of NASA s PSP mission there was a large amount of radio activity and, in particular, a noise storm of frequent, small type III bursts from 31 March to 6 April 2019. Our aim is to investigate the source of these small and frequent bursts. Methods: In order to do this, we analysed data from the Hinode EUV Imaging Spectrometer, PSP FIELDS, and ... Harra, L.; Brooks, D.; Bale, S.; Mandrini, C.; Barczynski, K.; Sharma, R.; Badman, S.; Domínguez, Vargas; Pulupa, M.; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202039514 Direct evidence for magnetic reconnection at the boundaries of magnetic switchbacks with Parker Solar Probe Context. The first encounters of Parker Solar Probe (PSP) with the Sun revealed the presence of ubiquitous localised magnetic deflections in the inner heliosphere; these structures, often called switchbacks, are particularly striking in solar wind streams originating from coronal holes. Aims: We report the direct piece of evidence for magnetic reconnection occurring at the boundaries of three switchbacks crossed by PSP at a distance of 45 to 48 solar radii to the Sun during its first encounter. Methods: We anal ... Froment, C.; Krasnoselskikh, V.; de Wit, Dudok; Agapitov, O.; Fargette, N.; Lavraud, B.; Larosa, A.; Kretzschmar, M.; Jagarlamudi, V.; Velli, M.; Malaspina, D.; Whittlesey, P.; Bale, S.; Case, A.; Goetz, K.; Kasper, J.; Korreck, K.; Larson, D.; MacDowall, R.; Mozer, F.; Pulupa, M.; Revillet, C.; Stevens, M.; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202039806 Switchbacks: statistical properties and deviations from Alfvénicity Context. Parker Solar Probe s first solar encounter has revealed the presence of sudden magnetic field deflections in the slow Alfvénic solar wind. These structures, which are often called switchbacks, are associated with proton velocity enhancements. Aims: We study their statistical properties with a special focus on their boundaries. Methods: Using data from SWEAP and FIELDS, we investigate particle and wavefield properties. The magnetic boundaries are analyzed with the minimum variance technique. Res ... Larosa, A.; Krasnoselskikh, V.; de Wit, Dudok; Agapitov, O.; Froment, C.; Jagarlamudi, V.; Velli, M.; Bale, S.; Case, A.; Goetz, K.; Harvey, P.; Kasper, J.; Korreck, K.; Larson, D.; MacDowall, R.; Malaspina, D.; Pulupa, M.; Revillet, C.; Stevens, M.; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202039442 Turbulent Proton Heating Rate in the Solar Wind from 545 R Various remote sensing observations have been used so far to probe the turbulent properties of the solar wind. Using the recently reported density modulation indices that are derived using angular broadening observations of Crab Nebula during 19522013, we measured the solar wind proton heating using the kinetic Alfvn wave dispersion equation. The estimated heating rates vary from 1.58 1014 to 1.01 108 erg cm3 s1 in the heliocentric distance range of 545 R. Further, we found that he ... Raja, Sasikumar; Subramanian, Prasad; Ingale, Madhusudan; Ramesh, R.; Maksimovic, Milan; Published by: The Astrophysical Journal      Published on: 06/2021 YEAR: 2021     DOI: 10.3847/1538-4357/abfcd1 Could Switchbacks Originate in the Lower Solar Atmosphere? II. Propagation of Switchbacks in the Solar Corona The magnetic switchbacks observed recently by the Parker Solar Probe have raised the question about their nature and origin. One of the competing theories of their origin is the interchange reconnection in the solar corona. In this scenario, switchbacks are generated at the reconnection site between open and closed magnetic fields, and are either advected by an upflow or propagate as waves into the solar wind. In this paper we test the wave hypothesis, numerically modeling the propagation of a switchback, modeled as an embed ... Magyar, Norbert; Utz, Dominik; Erdélyi, Robertus; Nakariakov, Valery; Published by: The Astrophysical Journal      Published on: 06/2021 YEAR: 2021     DOI: 10.3847/1538-4357/abfa98 Using Parker Solar Probe observations during the first four perihelia to constrain global magnetohydrodynamic models Context. Parker Solar Probe (PSP) is providing an unprecedented view of the Sun s corona as it progressively dips closer into the solar atmosphere with each solar encounter. Each set of observations provides a unique opportunity to test and constrain global models of the solar corona and inner heliosphere and, in turn, use the model results to provide a global context for interpreting such observations. Aims: In this study, we develop a set of global magnetohydrodynamic (MHD) model solutions of varying degrees of soph ... Riley, Pete; Lionello, Roberto; Caplan, Ronald; Downs, Cooper; Linker, Jon; Badman, Samuel; Stevens, Michael; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202039815 Discontinuity analysis of the leading switchback transition regions Context. Magnetic switchbacks are magnetic structures characterized as intervals of sudden reversal in the radial component of the pristine solar wind s magnetic field. Switchbacks comprise of magnetic spikes that are preceded and succeeded by switchback transition regions within which the radial magnetic field reverses. Determining switchback generation and evolution mechanisms will further our understanding of the global circulation and transportation of the Sun s open magnetic flux. Aims: The present study juxtapos ... Akhavan-Tafti, M.; Kasper, J.; Huang, J.; Bale, S.; Published by: Astronomy and Astrophysics      Published on: 06/2021 YEAR: 2021     DOI: 10.1051/0004-6361/202039508 Evolution of Solar Wind Turbulence from 0.1 to 1 au during the First Parker Solar Probe-Solar Orbiter Radial Alignment The first radial alignment between Parker Solar Probe and Solar Orbiter spacecraft is used to investigate the evolution of solar wind turbulence in the inner heliosphere. Assuming ballistic propagation, two 1.5 hr intervals are tentatively identified as providing measurements of the same plasma parcels traveling from 0.1 to 1 au. Using magnetic field measurements from both spacecraft, the properties of turbulence in the two intervals are assessed. Magnetic spectral density, flatness, and high-order moment scaling laws are ca ... Telloni, Daniele; Sorriso-Valvo, Luca; Woodham, Lloyd; Panasenco, Olga; Velli, Marco; Carbone, Francesco; Zank, Gary; Bruno, Roberto; Perrone, Denise; Nakanotani, Masaru; Shi, Chen; Amicis, Raffaella; De Marco, Rossana; Jagarlamudi, Vamsee; Steinvall, Konrad; Marino, Raffaele; Adhikari, Laxman; Zhao, Lingling; Liang, Haoming; Tenerani, Anna; Laker, Ronan; Horbury, Timothy; Bale, Stuart; Pulupa, Marc; Malaspina, David; MacDowall, Robert; Goetz, Keith; de Wit, Thierry; Harvey, Peter; Kasper, Justin; Korreck, Kelly; Larson, Davin; Case, Anthony; Stevens, Michael; Whittlesey, Phyllis; Livi, Roberto; Owen, Christopher; Livi, Stefano; Louarn, Philippe; Antonucci, Ester; Romoli, Marco; Brien, Helen; Evans, Vincent; Angelini, Virginia; Published by: The Astrophysical Journal      Published on: 05/2021 YEAR: 2021     DOI: 10.3847/2041-8213/abf7d1 Plasma dynamics in low-electron-beta environments Recent in situ measurements by the MMS and Parker Solar Probe missions bring interest to small-scale plasma dynamics (waves, turbulence, magnetic reconnection) in regions where the electron thermal energy is smaller than the magnetic one. Examples of such regions are the Earth s mangetosheath and the vicinity of the solar corona, and they are also encountered in other astrophysical systems. In this brief review, we consider simple physical models describing plasma dynamics in such low-electron-beta regimes, discuss their con ... Boldyrev, Stanislav; Loureiro, Nuno; Roytershteyn, Vadim; Published by: Frontiers in Astronomy and Space Sciences      Published on: 05/2021 YEAR: 2021     DOI: 10.3389/fspas.2021.621040 Correlation of the Sunspot Number and the Waiting-time Distribution of Solar Flares, Coronal Mass Ejections, and Solar Wind Switchback Events Observed with the Parker Solar Probe Waiting-time distributions of solar flares and coronal mass ejections (CMEs) exhibit power-law-like distribution functions with slopes in the range of ατ ≍ 1.4-3.2, as observed in annual data sets during four solar cycles (1974-2012). We find a close correlation between the waiting-time power-law slope ατ and the sunspot number (SN), i.e., ατ = 1.38 + 0.01 × SN. The waiting-time distribution can be fitted with a Pareto-type function of the form N(τ) = N0 \$(\tau _0+\tau )^ ... Aschwanden, Markus; de Wit, Thierry; Published by: The Astrophysical Journal      Published on: 05/2021 YEAR: 2021     DOI: 10.3847/1538-4357/abef69 Multiscale Solar Wind Turbulence Properties inside and near Switchbacks Measured by the Parker Solar Probe The Parker Solar Probe (PSP) routinely observes magnetic field deflections in the solar wind at distances less than 0.3 au from the Sun. These deflections are related to structures commonly called "switchbacks" (SBs), whose origins and characteristic properties are currently debated. Here, we use a database of visually selected SB intervals—and regions of solar wind plasma measured just before and after each SB—to examine plasma parameters, turbulent spectra from inertial to dissipation scales, and intermittency ... Martinovic, Mihailo; Klein, Kristopher; Huang, Jia; Chandran, Benjamin; Kasper, Justin; Lichko, Emily; Bowen, Trevor; Chen, Christopher; Matteini, Lorenzo; Stevens, Michael; Case, Anthony; Bale, Stuart; Published by: The Astrophysical Journal      Published on: 05/2021 YEAR: 2021     DOI: 10.3847/1538-4357/abebe5 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 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

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