# PSP Bibliography

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## Found 838 entries in the Bibliography.

### Showing entries from 101 through 150

 2022 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 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 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 Modeling Ion Beams, Kinetic Instabilities, and Waves Observed by the Parker Solar Probe near Perihelia 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 Multiband Electrostatic Waves below and above the Electron Cyclotron Frequency in the Near-Sun Solar Wind Using the Parker Solar Probe measurements, this Letter reports two new types of multiband electrostatic waves in and near the heliospheric current sheet. They are classified into the f < f $_ce$ and f > f $_ce$ multiband electrostatic waves, in which most (or all) of the bands in the former type are lower than f $_ce$, and all of the bands in the latter type are higher than f $_ce$, where f and f $_ce$ denotes the wave frequency and the electron cyclotron frequency, respectively. This Letter also exhibits observational evide ... Shi, Chen; Zhao, Jinsong; Malaspina, David; Bale, Stuart; Dong, Xiangcheng; Wang, Tieyan; Wu, Dejin; Published by: \apjl      Published on: feb YEAR: 2022     DOI: 10.3847/2041-8213/ac4d37 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 Double-power-law Feature of Energetic Particles Accelerated at Coronal Shocks Recent observations have shown that in many large solar energetic particle (SEP) events the event-integrated differential spectra resemble double power laws. We perform numerical modeling of particle acceleration at coronal shocks propagating through a streamer-like magnetic field by solving the Parker transport equation, including protons and heavier ions. We find that for all ion species the energy spectra integrated over the simulation domain can be described by a double power law, and the break energy depends on the ion ... Yu, Feiyu; Kong, Xiangliang; Guo, Fan; Liu, Wenlong; Jiang, Zelong; Chen, Yao; Giacalone, Joe; Published by: \apjl      Published on: feb YEAR: 2022     DOI: 10.3847/2041-8213/ac4cb3 The Stability of the Electron Strahl against the Oblique Fast-magnetosonic/Whistler Instability in the Inner Heliosphere 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 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 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 Sub-Alfv\ enic Solar Wind Observed by the Parker Solar Probe: Characterization of Turbulence, Anisotropy, Intermittency, and Switchback 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 PSP/IS\ensuremath\odotIS Observation of a Solar Energetic Particle Event Associated with a Streamer Blowout Coronal Mass Ejection during Encounter 6 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 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 Tracking of magnetic helicity evolution in the inner heliosphere. A radial alignment study Context. Magnetic helicity is one of the invariants in ideal magnetohydrodynamics, and its spectral evolution has a substantial amount of information to reveal the mechanism that are behind turbulence in space and astrophysical plasmas. \ Aims: The goal of our study is to observationally characterize the magnetic helicity evolution in the inner heliosphere by resolving the helicity transport in a scale-wise fashion in the spectral domain. \ Methods: The evolution of the magnetic helicity spectrum in the inner heliosphere was ... Alberti, T.; Narita, Y.; Hadid, L.~Z.; Heyner, D.; Milillo, A.; Plainaki, C.; Auster, H.; Richter, I.; Published by: \aap Published on: aug YEAR: 2022 DOI: 10.1051/0004-6361/202244314 Whistler waves shown to disappear close to the Sun An analysis of data from NASA s Parker Solar Probe has revealed that electromagnetic whistler waves are unexpectedly absent from certain regions of the Sun s upper atmosphere. e, Isabelle; Published by: Physics World Published on: aug YEAR: 2022 DOI: 10.1088/2058-7058/35/04/08 Parker Data Used Small-Scale Magnetic Holes in the Solar Wind Observed by Parker Solar Probe The small-scale magnetic hole (SSMH), characterized by magnetic field depression, is a structure with the size in the order of proton gyro-radius. SSMHs near the Earth or other planets have been widely observed in recent years. However, SSMHs in the solar wind near the Sun are rarely investigated due to mission constraints. In the present study, SSMHs in the pristine solar wind within a wide heliocentric distance range are analyzed based on the Parker Solar Probe (PSP) Mission measurements. A total of 2,416 SSMHs are success ... Yu, L.; Huang, S.~Y.; Yuan, Z.~G.; Jiang, K.; Wei, Y.~Y.; Zhang, J.; Xu, S.~B.; Xiong, Q.~Y.; Wang, Z.; Lin, R.~T.; Li, Y.~J.; Wang, C.~M.; Song, G.~J.; Published by: Journal of Geophysical Research (Space Physics) Published on: aug YEAR: 2022 DOI: 10.1029/2022JA030505 A magnetic flux rope configuration derived by optimization of two-spacecraft In-situ measurements Increasingly one interplanetary coronal mass ejection (ICME) structure can propagate across more than one spacecraft in the solar wind. This usually happens when two or more spacecraft are nearly radially aligned with a relatively small longitudinal separation angle from one another. This provides multi-point measurements of the same structure and enables better characterization and validation of modeling results of the structures embedded in these ICMEs. We report such an event during October 13-14, 2019 when the Solar TErr ... Hu, Qiang; He, Wen; Chen, Yu; Published by: Frontiers in Physics Published on: aug YEAR: 2022 DOI: 10.3389/fphy.2022.960315 Solar Chromospheric Network as a Source for Solar Wind Switchbacks Recent studies suggest that the magnetic switchbacks (SBs) detected by the Parker Solar Probe carry information on the scales of solar supergranulation (large scale) and granulation (medium scale). We test this claim using high-resolution H\ensuremath\alpha images obtained with the visible spectropolarimeters of the Goode Solar Telescope in Big Bear Solar Observatory. As possible solar sources, we count all the spicule-like features standing along the chromospheric networks near the coronal hole boundary visible in the H\ens ... Lee, Jeongwoo; Yurchyshyn, Vasyl; Wang, Haimin; Yang, Xu; Cao, Wenda; Oliveros, Juan; Published by: \apjl Published on: aug YEAR: 2022 DOI: 10.3847/2041-8213/ac86bf An orbital model for the Parker Solar Probe mission: Classical vs relativistic effects The Parker Solar Probe is a spacecraft designed to study the Sun s corona from inside. It is providing unprecedented detailed information on the density and composition of the Sun s atmosphere as well as the electromagnetic fields, plasma and solar wind. On the other hand, this probe is to achieve record speeds in the International Celestial Reference Frame (ICRF) never obtained before in any previous mission. It is expected that in the last perihelion of 2025 it would move at 0.064 \% of the speed of light with respect to t ... an, Sebasti\; Acedo, L.; Mora\~no, J.~A.; Published by: Advances in Space Research Published on: aug YEAR: 2022 DOI: 10.1016/j.asr.2022.05.037 Scaling of Electron Heating by Magnetization During Reconnection and Applications to Dipolarization Fronts and Super-Hot Solar Flares Electron ring velocity space distributions have previously been seen in numerical simulations of magnetic reconnection exhausts and have been suggested to be caused by the magnetization of the electron outflow jet by the compressed reconnected magnetic fields Barbhuiya, Hasan; Cassak, P.~A.; Shay, M.~A.; Roytershteyn, Vadim; Swisdak, M.; Caspi, Amir; Runov, Andrei; Liang, Haoming; Published by: Journal of Geophysical Research (Space Physics) Published on: aug YEAR: 2022 DOI: 10.1029/2022JA030610 Plasma Turbulence in the Near-Sun and Near-Earth Solar Wind: A Comparison via Observation-Driven 2D Hybrid Simulations Franci, Luca; Papini, Emanuele; Del Sarto, Daniele; Hellinger, Petr; Burgess, David; Matteini, Lorenzo; Landi, Simone; Montagud-Camps, Victor; Published by: Universe Published on: aug YEAR: 2022 DOI: 10.3390/universe8090453 Parker Data Used 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 Magnetic Field Dropouts and Associated Plasma Wave Emission near the Electron Plasma Frequency at Switchback Boundaries as Observed by the Parker Solar Probe The first solar encounters by the Parker Solar Probe revealed the magnetic field to be dominated by short field reversals in the radial direction, referred to as switchbacks. While radial velocity and proton temperature were shown to increase inside the switchbacks, \ensuremath\midB\ensuremath\mid exhibits very brief dropouts only at the switchback boundaries. Brief intensifications in spectral density measurements near the electron plasma frequency, f$_pe$, were also observed at these boundaries, indicating the presenc ... Rasca, Anthony; Farrell, William; Whittlesey, Phyllis; MacDowall, Robert; Bale, Stuart; Kasper, Justin; Published by: \apj Published on: aug YEAR: 2022 DOI: 10.3847/1538-4357/ac80c3 New Insights into the First Two PSP Solar Encounters Enabled by Modeling Analysis with ADAPT-WSA Parker Solar Probe s (PSP s) unique orbital path allows us to observe the solar wind closer to the Sun than ever before. Essential to advancing our knowledge of solar wind and energetic particle formation is identifying the sources of PSP observations. We report on results for the first two PSP solar encounters derived using the Wang-Sheeley-Arge (WSA) model driven by Air Force Data Assimilative Photospheric Flux Transport (ADAPT) model maps. We derive the coronal magnetic field and the 1 R$_\ensuremath\odot$source regions ... Wallace, Samantha; Jones, Shaela; Arge, Nick; Viall, Nicholeen; Henney, Carl; Published by: \apj Published on: aug YEAR: 2022 DOI: 10.3847/1538-4357/ac731c Turbulence and Waves in the Sub-Alfv\ enic Solar Wind Observed by the Parker Solar Probe during Encounter 10 During its 10th orbit around the Sun, the Parker Solar Probe sampled two intervals where the local Alfv\ en speed exceeded the solar wind speed, lasting more than 10 hours in total. In this paper, we analyze the turbulence and wave properties during these periods. The turbulence is observed to be Alfv\ enic and unbalanced, dominated by outward-propagating modes. The power spectrum of the outward-propagating Elsässer z$^+$mode steepens at high frequencies while that of the inward- propagating z$^-$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 Using Single-view Observations of Cometary Plasma Tails to Infer Solar Wind Speed A comet plasma tail is a product of the interaction between the solar wind and the comet s coma, and has long been studied as a natural probe of the solar wind condition. We previously developed a method to derive the solar wind speed from dual-view observations of comet plasma tails. Here we improve the method to use single-view observations by assuming a radially propagating solar wind and apply it to two comets, C/2011 W3 (Lovejoy) and C/2012 S1 (ISON) observed by coronagraphs on board the Solar and Heliospheric Observato ... Cheng, Long; Wang, Yuming; Li, Xiaolei; Published by: \apj Published on: apr YEAR: 2022 DOI: 10.3847/1538-4357/ac5410 Plasma Parameters From Quasi-Thermal Noise Observed by Parker Solar Probe: A New Model for the Antenna Response Quasi-Thermal Noise (QTN) spectroscopy is a reliable diagnostic routinely used for measuring electron density and temperature in space plasmas. The observed spectrum depends on both antenna geometry and plasma kinetic properties. Parker solar probe (PSP), launched in 2018, is equipped with an antenna system consisting of two linear dipoles with a significant gap between the antenna arms. Such a configuration, not utilized on previous missions, cannot be completely described by current models of the antenna response function. ... c, Mihailo; c, Antonije; Klein, Kristopher; c, Milan; Issautier, Karine; Liu, Mingzhe; Pulupa, Marc; Bale, Stuart; Halekas, Jasper; McManus, Michael; Published by: Journal of Geophysical Research (Space Physics) Published on: apr YEAR: 2022 DOI: 10.1029/2021JA030182 First Results From the SCM Search-Coil Magnetometer on Parker Solar Probe Parker Solar Probe is the first mission to probe in situ the innermost heliosphere, revealing an exceptionally dynamic and structured outer solar corona. Its payload includes a search-coil magnetometer (SCM) that measures up to three components of the fluctuating magnetic field between 3 Hz and 1 MHz. After more than 3 years of operation, the SCM has revealed a multitude of different wave phenomena in the solar wind. Here we present an overview of some of the discoveries made so far. These include oblique and sunward propaga ... de Wit, Dudok; Krasnoselskikh, V.~V.; Agapitov, O.; Froment, C.; Larosa, A.; Bale, S.~D.; Bowen, T.; Goetz, K.; Harvey, P.; Jannet, G.; Kretzschmar, M.; MacDowall, R.~J.; Malaspina, D.; Martin, P.; Page, B.; Pulupa, M.; Revillet, C.; Published by: Journal of Geophysical Research (Space Physics) Published on: apr YEAR: 2022 DOI: 10.1029/2021JA030018 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 The Dynamic Coupling of Streamers and Pseudostreamers to the Heliosphere The slow solar wind is generally believed to result from the interaction of open and closed coronal magnetic flux at streamers and pseudostreamers. We use three-dimensional magnetohydrodynamic simulations to determine the detailed structure and dynamics of open-closed interactions that are driven by photospheric convective flows. The photospheric magnetic field model includes a global dipole giving rise to a streamer together with a large parasitic polarity region giving rise to a pseudostreamer that separates a satellite co ... Aslanyan, V.; Pontin, D.~I.; Higginson, A.~K.; Wyper, P.~F.; Scott, R.~B.; Antiochos, S.~K.; Published by: \apj Published on: apr YEAR: 2022 DOI: 10.3847/1538-4357/ac5d5b Possible Evidence for Shear-driven Kelvin-Helmholtz Instability along the Boundary of Fast and Slow Solar Wind in the Corona This paper reports the first possible evidence for the development of the Kelvin-Helmholtz (KH) instability at the border of coronal holes separating the associated fast wind from the slower wind originating from adjacent streamer regions. Based on a statistical data set of spectroscopic measurements of the UV corona acquired with the UltraViolet Coronagraph Spectrometer on board the SOlar and Heliospheric Observatory during the minimum activity of solar cycle 22, high temperature-velocity correlations are found along the fa ... Telloni, Daniele; Adhikari, Laxman; Zank, Gary; Zhao, Lingling; Sorriso-Valvo, Luca; Antonucci, Ester; Giordano, Silvio; Mancuso, Salvatore; Published by: \apj Published on: apr YEAR: 2022 DOI: 10.3847/1538-4357/ac5cc3 Solar Wind Model Supported by Parker Solar Probe Observations During Faint Venusian Auroral Emission The encounter of the Parker Solar Probe (PSP) with Venus during the Venus Gravity Assist 3 on 2020 July 11 provided a unique opportunity to gather in situ solar wind data in the Venusian environment while also being able to observe Venus from ground- based facilities on Earth. The Wang-Sheeley-Arge (WSA) model was used to make accurate predictions of solar wind velocity and interplanetary magnetic field polarity at Earth and STEREO-A, as compared to in situ data at each spacecraft. The same model was then used to predict sol ... Kovac, Sarah; Gray, Candace; Arge, Nick; Chanover, Nancy; Churchill, Christopher; Szabo, Adam; Hill, Matthew; McAteer, James; Published by: \apj Published on: apr YEAR: 2022 DOI: 10.3847/1538-4357/ac58f4 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 Validation of a Wave Heated 3D MHD Coronal-wind Model using Polarized Brightness and EUV Observations The physical properties responsible for the formation and evolution of the corona and heliosphere are still not completely understood. 3D MHD global modeling is a powerful tool to investigate all the possible candidate processes. To fully understand the role of each of them, we need a validation process where the output from the simulations is quantitatively compared to the observational data. In this work, we present the results from our validation process applied to the wave turbulence driven 3D MHD corona-wind model WindP ... Parenti, Susanna; eville, Victor; Brun, Allan; Pinto, Rui; Auchère, Fr\; Buchlin, Eric; Perri, Barbara; Strugarek, Antoine; Published by: \apj Published on: apr YEAR: 2022 DOI: 10.3847/1538-4357/ac56da The first widespread solar energetic particle event of solar cycle 25 on 2020 November 29. Shock wave properties and the wide distribution of solar energetic particles Context. On 2020 November 29, an eruptive event occurred in an active region located behind the eastern solar limb as seen from Earth. The event consisted of an M4.4 class flare, a coronal mass ejection, an extreme ultraviolet (EUV) wave, and a white-light (WL) shock wave. The eruption gave rise to the first widespread solar energetic particle (SEP) event of solar cycle 25, which was observed at four widely separated heliospheric locations (\ensuremath\sim230\textdegree). \ Aims: Our aim is to better understand the source of ... Kouloumvakos, A.; Kwon, R.~Y.; ia, Rodr\; Lario, D.; Dresing, N.; Kilpua, E.~K.~J.; Vainio, R.; Török, T.; Plotnikov, I.; Rouillard, A.~P.; Downs, C.; Linker, J.~A.; Malandraki, O.~E.; Pinto, R.~F.; Riley, P.; Allen, R.~C.; Published by: \aap Published on: apr YEAR: 2022 DOI: 10.1051/0004-6361/202142515 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}$resolution. In te ... Lotekar, A.~B.; Vasko, I.~Y.; Phan, T.; Bale, S.~D.; Bowen, T.~A.; Halekas, J.; Artemyev, A.~V.; Khotyaintsev, Yu.; Mozer, F.~S.; Published by: \apj Published on: apr YEAR: 2022 DOI: 10.3847/1538-4357/ac5bd9 2021 Nonlinear Wave-Wave Coupling Related to Whistler-mode and Electron Bernstein Waves Observed by the Parker Solar Probe We report nonlinear wave-wave coupling related to whistler-mode or electron Bernstein waves in the near-Sun slow solar wind with Parker Solar Probe (PSP) data. Prominent plasma wave power enhancements usually exist near the electron gyrofrequency (f$_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 Icarus: In-situ monitoring of the surface degradation on a near-Sun asteroid Icarus is a mission concept designed to record the activity of an asteroid during a close encounter with the Sun. The primary science goal of the mission is to unravel the nontrivial mechanism(s) that destroy asteroids on orbits with small perihelion distances. Understanding the destruction mechanism(s) allows us to constrain the bulk composition and interior structure of asteroids in general. The Icarus mission does not only aim to achieve its science goals but also functions as a technical demonstration of what a low-cost ... Lehtinen, Tuomas; Granvik, Mikael; Bellome, Andrea; anchez, Joan-Pau; Published by: Acta Astronautica Published on: sep YEAR: 2021 DOI: 10.1016/j.actaastro.2021.05.028 Parker solar probe observations of helical structures as boundaries for energetic particles Energetic particle transport in the interplanetary medium is known to be affected by magnetic structures. It has been demonstrated for solar energetic particles in near-Earth orbit studies, and also for the more energetic cosmic rays. In this paper, we show observational evidence that intensity variations of solar energetic particles can be correlated with the occurrence of helical magnetic flux tubes and their boundaries. The analysis is carried out using data from Parker Solar Probe orbit 5, in the period 2020 May 24 to Ju ... Pecora, F.; Servidio, S.; Greco, A.; Matthaeus, W.~H.; McComas, D.~J.; Giacalone, J.; Joyce, C.~J.; Getachew, T.; Cohen, C.~M.~S.; Leske, R.~A.; Wiedenbeck, M.~E.; McNutt, R.~L.; Hill, M.~E.; Mitchell, D.~G.; Christian, E.~R.; Roelof, E.~C.; Schwadron, N.~A.; Bale, S.~D.; Published by: \mnras Published on: sep YEAR: 2021 DOI: 10.1093/mnras/stab2659 Toward a Physics Based Model of Hypervelocity Dust Impacts There has been important understanding of the process by which a hypersonic dust impact makes an electrical signal on a spacecraft sensor, leading to a fuller understanding of the Kellogg, Paul; Bale, S.~D.; Goetz, Keith; Monson, Steven; Published by: Journal of Geophysical Research (Space Physics) Published on: sep YEAR: 2021 DOI: 10.1029/2020JA028415 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