Related papers: Characteristics and Source Regions of Slow Alfveni…
We seek to understand the composition and variability of fast (FSW) and slow Alfvenic solar wind (SASW) emerging from coronal holes (CH). We leverage an opportune conjunction between Solar Orbiter and Parker Solar Probe (PSP) during PSP…
Fast and slow solar wind have distinct properties linked to their solar sources.Alfv\'enic slow wind complicates the usual speed-based classification, especially at intermediate speeds. Solar Orbiter's Solar Wind Analyzer (SWA) offers…
During Parker Solar Probe (Parker) Encounter 15 (E15), we observe an 18-hour period of near subsonic ($\mathrm{M_S \sim}$ 1) and sub-Alfv\'enic (SA), $\mathrm{M_A}$ <<< 1, slow speed solar wind from 22 to 15.6 R$_\odot$. As the most extreme…
Slow solar wind is typically characterized as having low Alfv\'enicity, but the occasional occurrence of highly Alfv\'enic slow solar wind (HASSW) raises questions about its source regions and evolution. In this work, we conduct a…
Close to Earth the solar wind is usually super-Alfv\'enic, i.e. the speed of the solar wind is much larger than the Alfv\'en speed. However, in the lower coronal regions, the solar wind is mostly sub-Alfv\'enic. With the Parker Solar Probe…
We identify more than ten steady sub-Alfv\'enic solar wind intervals from the measurements of the Parker Solar Probe (PSP) from encounter 8 to encounter 14. An analysis of these sub-Alfv\'enic intervals reveals similar properties and…
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…
In the lower solar coronal regions where the magnetic field is dominant, the Alfven speed is much higher than the wind speed. In contrast, the near-Earth solar wind is strongly super-Alfvenic, i.e., the wind speed greatly exceeds the Alfven…
Although the origins of slow solar wind are unclear, there is increasing evidence that at least some of it is released in a steady state on over-expanded coronal hole magnetic field lines. This type of slow wind has similar properties to…
We identify and examine the solar wind intervals near the sonic critical point (i.e., $M_S \sim 1$) observed by the Parker Solar Probe (PSP). The near subsonic wind intervals show similar properties: a low density, an extremely low…
The Parker Solar Probe (PSP) provides us the unprecedentedly close approach observation to the Sun, and hence the possibility of directly understanding the "elementary process" which occurs in the kinetic scale of particles collective…
From 2022 March 18-21, active region (AR) 12967 was tracked simultaneously by Solar Orbiter (SO) at 0.35 au and Hinode/EIS at Earth. During this period, strong blue-shifted plasma upflows were observed along a thin, dark corridor of open…
We examine Alfv\'en Wave Solar atmosphere Model (AWSoM) predictions of the first Parker Solar Probe (PSP) encounter. We focus on the 12-day closest approach centered on the 1st perihelion. AWSoM (van der Holst et al., 2014) allows us to…
Past observations show that solar wind (SW) acceleration occurs inside the sub-Alfvenic region, reaching the local Alfven speed at typical distances ~ 10 - 20 Rs (solar radii). Recently, Parker Solar Probe (PSP) traversed regions of…
$PSP$ and $SolO$ data are utilized to investigate magnetic field intermittency in the solar wind (SW). Small-scale intermittency $(20-100d_{i})$ is observed to radially strengthen when methods relying on higher-order moments are considered…
The two-state solar wind paradigm is based on observations showing that slow and fast solar wind have distinct properties like helium abundances, kinetic signatures, elemental composition, and charge-state ratios. Nominally, the fast wind…
In the corona, plasma is accelerated to hundreds of kilometers per second, and heated to temperatures hundreds of times hotter than the Sun's surface, before it escapes to form the solar wind. Decades of space-based experiments have shown…
Alfv\'enic fluctuations are very common features in the solar wind and are found especially within the main portion of fast wind streams while the slow wind usually is less Alfv\'enic and more variable. In general, fast and slow wind show…
Two states of the slow solar wind are identified from in-situ measurements by Parker Solar Probe (PSP) inside 50 solar radii from the Sun. At such distances the wind measured at PSP has not yet undergone significant transformation related…
Parker Solar Probe (PSP) entered a region of the sub-Alfvenic 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…