A5050201056- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Astro and Planetary Science
- Geomagnetism and Paleomagnetism Studies
- Solar Radiation and Photovoltaics
- Stellar, planetary, and galactic studies
- Geophysics and Gravity Measurements
- Planetary Science and Exploration
- Earthquake Detection and Analysis
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Magnetic confinement fusion research
- Photovoltaic System Optimization Techniques
- Radiation Therapy and Dosimetry
- Spacecraft Design and Technology
- Advanced Thermodynamics and Statistical Mechanics
- Electron and X-Ray Spectroscopy Techniques
- Solar Thermal and Photovoltaic Systems
- solar cell performance optimization
- Photocathodes and Microchannel Plates
- Electromagnetic Compatibility and Measurements
- Energy Harvesting in Wireless Networks
- Space Satellite Systems and Control
- Tropical and Extratropical Cyclones Research
University of California, Berkeley
2016-2025
Goddard Space Flight Center
2021
1366 Technologies (United States)
2021
University of Michigan–Ann Arbor
2021
University of Arizona
2020
Berkeley College
2008
The first two orbits of the Parker Solar Probe (PSP) spacecraft have enabled in situ measurements solar wind down to a heliocentric distance 0.17 au (or 36 Rs). Here, we present an analysis this data study turbulence at and its evolution out 1 au. While many features remain similar, key differences include: increased energy levels by more than order magnitude, magnetic field spectral index -3/2 matching that velocity both Elsasser fields, lower compressibility consistent with smaller...
One of the most striking observations made by Parker Solar Probe during its first solar encounter is omnipresence rapid polarity reversals in a magnetic field that otherwise mostly radial. These so-called switchbacks strongly affect dynamics field. We concentrate here on their macroscopic properties. First, we find these structures are self-similar, and have neither characteristic magnitude, nor duration. Their waiting time statistics shows evidence for aggregation. The associated long...
Abstract Launched on 12 Aug. 2018, NASA’s Parker Solar Probe had completed 13 of its scheduled 24 orbits around the Sun by Nov. 2022. The mission’s primary science goal is to determine structure and dynamics Sun’s coronal magnetic field, understand how solar corona wind are heated accelerated, what processes accelerate energetic particles. returned a treasure trove data that far exceeded quality, significance, quantity expectations, leading significant number discoveries reported in nearly...
Heat transport in the solar corona and wind is still a major unsolved astrophysical problem. Because of key role played by electrons, electron density temperature(s) are important prerequisites for understanding these plasmas. We present such situ measurements along two first encounters Parker Solar Probe (PSP), between 0.5 0.17 AU from Sun, revealing different states emerging near activity minimum. These preliminary results obtained simplified analysis plasma quasi-thermal noise (QTN)...
The Solar Wind Electrons Alphas and Protons experiment on the Parker Probe (PSP) mission measures three-dimensional electron velocity distribution function. We derive parameters of core, halo, strahl populations utilizing a combination fitting to model distributions numerical integration for $\sim 100,000$ measured near Sun first two PSP orbits, which reached heliocentric distances as small 0.17$ AU. As expected, core density temperature increase with decreasing distance, while ratio thermal...
Abstract Measurements of the near-Sun solar wind by Parker Solar Probe have revealed presence large numbers discrete Alfvénic impulses with an anti-sunward sense propagation. These are similar to those previously observed near 1 au, in high speed streams over Sun’s poles and at 60 radii. At 35 radii, however, they typically shorter sharper than seen elsewhere. In addition, these spikes occur “patches” there also clear periods within same stream when do not occur; timescale patches might be...
We present a statistical survey of ∼2–20 keV superhalo electrons in the solar wind measured by SupraThermal Electron instrument on board two STEREO spacecraft during quiet-time periods from 2007 March through 2009 at minimum. The observed have nearly isotropic angular distribution and power-law spectrum, f∝v−γ, with γ ranging 5 to 8.7, half between 6.5 7.5, an average index 6.69 ± 0.90. spectrum varies significantly spatial scale ≳0.1 AU temporal ≳several days. integrated density 2–20 ranges...
We present a long-duration ($\sim$10 years) statistical analysis of the temperatures, plasma betas, and temperature ratios for electron, proton, alpha-particle populations observed by \emph{Wind} spacecraft near 1 AU. The mean(median) scalar temperatures are $T{\scriptstyle_{e, tot}}$ $=$ 12.2(11.9) eV, $T{\scriptstyle_{p, 12.7(8.6) $T{\scriptstyle_{\alpha, 23.9(10.8) eV. total betas $\beta{\scriptstyle_{e, 2.31(1.09), $\beta{\scriptstyle_{p, 1.79(1.05), $\beta{\scriptstyle_{\alpha,...
The structure of magnetic flux ropes injected into the solar wind during reconnection in coronal atmosphere is explored with particle-in-cell simulations and compared situ measurements "switchbacks" from Parker Solar Probe. We suggest that multi-x-line between open closed corona injects these convect outward over long distances before eroding due to reconnection. Simulations explore reproduce following key features switchback observations: a rapid rotation radial field transverse direction,...
Abstract Parker Solar Probe ( PSP ) observations during its first encounter at 35.7 R ⊙ have shown the presence of magnetic field lines that are strongly perturbed to point they produce local inversions radial field, known as switchbacks. Their counterparts in solar wind velocity enhancements speed, or jets, displaying (in all components) velocity–magnetic correlation typical large amplitude Alfvén waves propagating away from Sun. Switchbacks and jets previously been observed over a wide...
The Radio Frequency Spectrometer (RFS) is a two‐channel digital receiver and spectrometer, which will make remote sensing observations of radio waves in situ measurements electrostatic electromagnetic fluctuations the solar wind. A part FIELDS suite for Solar Probe Plus (SPP), RFS optimized inner heliosphere, where bursts are more intense plasma frequency higher compared to previous at distances 1 AU or greater. inputs four electric antennas mounted near front SPP spacecraft single axis...
Abstract Switchbacks (rotations of the magnetic field) are observed on Parker Solar Probe . Their evolution, content, and plasma effects studied in this paper. The solar wind does not receive a net acceleration from switchbacks that it encountered upstream observation point. typical switchback rotation angle increased with radial distance. Significant Poynting fluxes existed inside, but outside, switchbacks, dependence flux amplitude location is explained quantitatively as being proportional...
Understanding the physical processes in solar wind and corona which actively contribute to heating, acceleration, dissipation is a primary objective of NASA's Parker Solar Probe (PSP) mission. Observations coherent electromagnetic waves at ion scales suggests that linear cyclotron resonance non-linear are dynamically relevant inner heliosphere. A wavelet-based statistical study first perihelion encounter PSP demonstrates presence transverse resonant observed 30-50\% radial field intervals....
Magnetic reconnection in current sheets converts magnetic energy into particle energy. The process may play an important role the acceleration and heating of solar wind close to Sun. Observations from Parker Solar Probe provide a new opportunity study this problem, as it measures at unprecedented distances During 1st orbit, PSP encountered large number through perihelion 35.7 radii. We performed comprehensive survey these found evidence for 21 exhausts. These exhausts were observed...
Abstract During Parker Solar Probe ’s first orbit, the solar wind plasma was observed in situ closer than ever before, perihelion on 2018 November 6 revealing a flow that is constantly permeated by large-amplitude Alfvénic fluctuations. These include radial magnetic field reversals, or switchbacks, seem to be persistent feature of young wind. The measurements also reveal very strong, unexpected, azimuthal velocity component. In this work, we numerically model corona during encounter, solving...
Abstract Parker Solar Probe (PSP), NASA’s latest and closest mission to the Sun, is on a journey investigate fundamental enigmas of inner heliosphere. This paper reports initial observations made by Analyzer for Ions (SPAN-I), one instruments in Wind Electrons Alphas Protons instrument suite. We address presence secondary proton beams concert with ion-scale waves observed FIELDS, electromagnetic fields show two events from PSP’s second orbit that demonstrate signatures consistent...
We consider 2D joint distributions of normalized residual energy, σr(s, t), and cross helicity, σc(s, during one day Parker Solar Probe's (PSP's) first encounter as a function wavelet scale s. The broad features the are similar to previous observations made by Helios in slow solar wind, namely well-correlated fairly Alfvénic except for population with negative helicity that is seen at shorter scales. show this due presence magnetic switchbacks, or brief periods where field polarity reverses....
Direct evidence of an inertial-range turbulent energy cascade has been provided by spacecraft observations in heliospheric plasmas. In the solar wind, average value derived heating rate near 1 au is $\sim 10^{3}\, \mathrm{J\,kg^{-1}\,s^{-1}}$, amount sufficient to account for observed departures from adiabatic expansion. Parker Solar Probe (PSP), even during its first encounter, offers opportunity compute, a similar fashion, fluid-scale decay rate, much closer corona than any prior in-situ...
We discuss the solar wind electron temperatures Te as measured in nascent by Parker Solar Probe during its first perihelion pass. The measurements have been obtained fitting high-frequency part of quasi-thermal noise spectra recorded Radio Frequency Spectrometer. In addition we compare these with those electrostatic analyzer discussed Halekas et al. These observations show an anticorrelation between and bulk speed V: this is most likely remnant well-known mapping observed at 1 au beyond fast...
Abstract The first radial alignment between Parker Solar Probe and Orbiter spacecraft is used to investigate the evolution of solar wind turbulence in inner heliosphere. Assuming ballistic propagation, two 1.5 hr intervals are tentatively identified as providing measurements same plasma parcels traveling from 0.1 1 au. Using magnetic field both spacecraft, properties assessed. Magnetic spectral density, flatness, high-order moment scaling laws calculated. Hilbert–Huang transform additionally...