Parker Solar Probe Bibliography

2016

The upcoming Solar Probe Plus mission (Launch 2018) will launch with the newest and fastest space plasma instrumentation to date. The Solar Wind Electrons, Alphas, and Protons (SWEAP) instrument suite, which measures thermal plasma, will make measurements faster than the local gyro-frequency and proton plasma frequency. By developing an end-to-end computer model of a SWEAP instrument, this work explores the specific instrumental effects of thermal space plasma measurement, particularly in the reproduction of velocity power spectra, or Power Spectral Densities (PSDs). This model reproduces the slowest measurement cadence of the Solar Probe Cup (SPC), a Faraday cup (PC) style instrument on that will measure thermal plasma density, velocity, and temperature on SPP. By using the calibrated model to model measurement of fully determined and synthetic turbulent time series data, a consistent underestimation of the velocity power spectral indices has been quantified, with possible…
2016


2015

<p>Knowledge of the electron density distribution in the solar corona put constraints on the magnetic field configurations for coronal modeling and on initial conditions for solar wind modeling. We work with polarized SOHO/LASCO-C2 images from the last two recent minima of solar activity (1996-1997 and 2008-2010), devoid of coronal mass ejections. The goals are to derive the 4D electron density distributions in the corona by applying a newly developed time-dependent tomographic reconstruction method and to compare the results between the two solar minima and with two magnetohydrodynamic models. First, we confirm that the values of the density distribution in thermodynamic models are more realistic than in polytropic ones. The tomography provides more accurate distributions in the polar regions, and we find that the density in tomographic and thermodynamic solutions varies with the solar cycle in both polar and equatorial regions. Second, we find that the highest-density…
2015


<p>The evolution of the ion-scale plasma turbulence in the inner heliosphere is studied by associating the plasma parameters for hybrid-code turbulence simulations to the radial distance from the Sun via a Solar wind model based mapping procedure. Using a mapping based on a one-dimensional solar wind expansion model, the resulting ion-kinetic scale turbulence is related to the solar wind distance from the Sun. For this purpose the mapping is carried out for various values of ion beta that correspond to the heliocentric distance. It is shown that the relevant normal modes such as ion cyclotron and ion Bernstein modes will occur first at radial distances of about 0.2-0.3 AU, i.e., near the Mercury orbit. This finding can be used as a reference, a prediction to guide the in situ measurements to be performed by the upcoming Solar Orbiter and Solar Probe Plus missions. Furthermore, a radial dependence of the wave-vector anisotropy was obtained. For astrophysical objects this means…
2015


<p>We extend the kinetic guiding-center model of collisionless coronal hole protons presented in Isenberg \&amp; Vasquez to consider driving by imbalanced spectra of obliquely propagating ion-cyclotron waves. These waves are assumed to be a small by-product of the imbalanced turbulent cascade to high perpendicular wavenumber, and their total intensity is taken to be 1\% of the total fluctuation energy. We also extend the kinetic solutions for the proton distribution function in the resulting fast solar wind to heliocentric distances of 20 solar radii, which will be attainable by the Solar Probe Plus spacecraft. We consider three ratios of outward-propagating to inward-propagating resonant intensities: 1, 4, and 9. The self-consistent bulk flow speed reaches fast solar wind values in all cases, and these speeds are basically independent of the intensity ratio. The steady-state proton distribution is highly organized into nested constant-density shells by the resonant wave-…
2015


<p>The Solar Probe Plus (SPP) spacecraft will explore the near-Sun environment, reaching heliocentric distances less than 10 R<sub>☉ </sub>. Near Earth, spacecraft measurements of fluctuating velocities and magnetic fields taken in the time domain are translated into information about the spatial structure of the solar wind via Taylor\textquoterights \textquotedblleftfrozen turbulence\textquotedblright hypothesis. Near the perihelion of SPP, however, the solar-wind speed is comparable to the Alfv\ en speed, and Taylor\textquoterights hypothesis in its usual form does not apply. In this paper, we show that under certain assumptions, a modified version of Taylor\textquoterights hypothesis can be recovered in the near-Sun region. We consider only the transverse, non-compressive component of the fluctuations at length scales exceeding the proton gyroradius, and we describe these fluctuations using an approximate theoretical framework developed by Heinemann and Olbert. We…
2015


<p>The Solar Orbiter and Solar Probe Plus missions will provide observations of magnetic clouds closer to the Sun than ever before, and it will be good preparation for these missions to make full use of the most recent in situ data sets from the inner heliosphere\textemdashnamely, those provided by MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) and Venus Express\textemdashfor magnetic cloud studies. We present observations of the same magnetic cloud made by MESSENGER at Mercury and later by Solar TErrestrial RElations Observatory-B (STEREO-B), while the spacecraft were radially aligned in 2011 November. Few such radial observations of magnetic clouds have been previously reported. Estimates of the solar wind speed at MESSENGER are also presented, calculated through the application of a previously established technique. The cloud\textquoterights flux rope has been analyzed using force-free fitting; the rope diameter increased from 0.18 to 0.41 AU (…
2015


<p>The paper provides a review of the state of the art and prospects of space research in heliophysics, in which a pivotal role belongs to magnetic measurements in the Sun and heliosphere. New space missions, such as the Interhelioprobe, Solar Orbiter, Solar Probe Plus, etc., will follow the currently operating ones (Hinode, SDO, STEREO, etc.) to observe the Sun from short distances and from out-of-ecliptic positions, as well as to conduct in situ measurements in the vicinity of the Sun and outside the ecliptic. The planned coordinated observations within the framework of these missions will allow us to explore the structure and dynamics of magnetic fields in the polar regions of the Sun, to study the mechanisms of the solar dynamo and solar cycle, to gain a deeper insight into the process of corona heating and acceleration of the solar wind, and to get a response to a number of other pressing issues of heliophysics.</p>
2015


<p>The Solar Wind Electrons Alphas and Protons (SWEAP) Investigation on Solar Probe Plus is a four sensor instrument suite that provides complete measurements of the electrons and ionized helium and hydrogen that constitute the bulk of solar wind and coronal plasma. SWEAP consists of the Solar Probe Cup (SPC) and the Solar Probe Analyzers (SPAN). SPC is a Faraday Cup that looks directly at the Sun and measures ion and electron fluxes and flow angles as a function of energy. SPAN consists of an ion and electron electrostatic analyzer (ESA) on the ram side of SPP (SPAN-A) and an electron ESA on the anti-ram side (SPAN-B). The SPAN-A ion ESA has a time of flight section that enables it to sort particles by their mass/charge ratio, permitting differentiation of ion species. SPAN-A and -B are rotated relative to one another so their broad fields of view combine like the seams on a baseball to view the entire sky except for the region obscured by the heat shield and covered by SPC.…
2015


<p>recent studies suggest that magnetic reconnection is able to erode substantial amounts of the outer magnetic flux of interplanetary magnetic clouds (MCs) as they propagate in the heliosphere. We quantify and provide a broader context to this process, starting from 263 tabulated interplanetary coronal mass ejections, including MCs, observed over a time period covering 17 years and at a distance of 1 AU from the Sun with Wind (1995-2008) and the two STEREO (2009-2012) spacecraft. Based on several quality factors, including careful determination of the MC boundaries and main magnetic flux rope axes, an analysis of the azimuthal flux imbalance expected from erosion by magnetic reconnection was performed on a subset of 50 MCs. The results suggest that MCs may be eroded at the front or at rear and in similar proportions, with a significant average erosion of about 40\% of the total azimuthal magnetic flux. We also searched for in situ signatures of magnetic reconnection causing…
2015


The size of relatively large dynamic conchoidal fractures, i.e., surface spalls, immediately adjacent to and around interplanetary dust (IDP) hypervelocity impact (HVI) craters or pits in glass substrates is relevant to spacecraft solar cell and science instrument lens performance metrics, as well as glass pane design and safety in manned missions. This paper presents an analysis of the diameter of surface spalls in glass for the Solar Probe Plus (SPP) spacecraft, whose solar arrays and instruments must survive a 7-year mission involving significant dust interaction. Previously published data and regressions for surface spalling obtained from ground-HVI-tested and space-returned glass samples and solar cells are collated for this purpose. Analysis of the collective dataset reveals an unexpected and design-relevant finding: spall diameter, D-S, obtained with dust-scale particles (diameter, d(P) < 55 mu m) and solar cells scales differently with impact velocity as compared with…
2015


Past papers demonstrated advancements made on developing scientific PMOS/NMOS CMOS imagers that match or exceed CCD performance. New data and discussions presented in this paper present further progress on subject matters that include: 1). subcarrier read noise performance with understandings for how the noise floor can be reduced further, 2). comprehensive correlated double sampling (CDS) signal processing noise fundamentals in response to random telegraph and flicker noise sources, 3). high energy radiation damage test data from NASA s BSI SoloHi/WISPR CMOS imager and 4). update on a new scientific BSI PMOS/NMOS stitched Mk x Nk x 10 um 5TPPD pixel imager being fabricated for Lawrence Livermore National Lab (LLNL) and NASA s Europa Clipper mission.
2015


Three metallic coatings with textured surfaces, made of rhenium, tungsten and molybdenum, were studied in the frame of the Solar Probe Plus mission (NASA) as candidate materials. The role of these coatings is to dissipate a maximum of energy from a hot instrument facing the Sun, by the mean of their high total hemispherical emissivity. The total hemispherical emissivity of the three coatings was measured in the temperature range 1100-1900 K, as well as over time in order to study their high temperature stability. Various emissivity levels were obtained depending on the surface texture. The highest total hemispherical emissivity was obtained on a rhenium coating, with an emissivity of 0.8 in the temperature range 1300-1700 K. However, this rhenium coating with a fine, sharp surface texture, presented an instability at high temperature, which might limit its optimal operating temperature to about 1500 K. As for the tungsten coating, the total hemispherical emissivity was increased by a…
2015


The Solar Probe Plus mission (NASA) will be the first mission to enter the solar corona. The spacecraft will orbit the Sun at 8.5 solar radii from the Sun s surface at closest approach. Some metallic parts of the two on-board instruments, SWEAP (a Faraday cup) and FIELDS (antennas), will directly face the Sun, while the rest of the payload will be protected by a heat shield. For application to these instruments, a candidate refractory material, tungsten, was studied, confronting conditions similar to the ones expected close to the Sun: high radiative flux leading to high temperatures (1100-2500 K) and proton bombardment (1 and 4 keV; 10(16), 10(17) and 10(18) ions m(-2) s(-1)) to simulate the solar wind in high vacuum (10(-4) Pa). Total directional and hemispherical emissivities in the two wavelength ranges 0.6-2.8 and 0.6-40 mu m were recorded in situ during treatments. Material characterization was performed before and after each high temperature and bombardment experiment to…
2015


2014

<p>Solar Probe Plus, scheduled to launch in 2018, is a NASA mission that will fly through the Sun\textquoterights atmosphere for the first time. It will employ a combination of in situ plasma measurements and remote sensing imaging to achieve the mission\textquoterights primary goal: to understand how the Sun\textquoterights corona is heated and how the solar wind is accelerated. The Solar Wind Electrons Alphas and Protons (SWEAP) instrument suite consists of a Faraday cup and three electrostatic analyzers. In order to accomplish the science objectives, an encounter-based operations scheme is needed. This paper will outline the SWEAP science operations center design and schemes for data selection and down link. \textcopyright (2014) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.</p>
2014


<p>The interpretation of single-point spacecraft measurements of solar wind turbulence is complicated by the fact that the measurements are made in a frame of reference in relative motion with respect to the turbulent plasma. The Taylor hypothesis\textemdashthat temporal fluctuations measured by a stationary probe in a rapidly flowing fluid are dominated by the advection of spatial structures in the fluid rest frame\textemdashis often assumed to simplify the analysis. But measurements of turbulence in upcoming missions, such as Solar Probe Plus, threaten to violate the Taylor hypothesis, either due to slow flow of the plasma with respect to the spacecraft or to the dispersive nature of the plasma fluctuations at small scales. Assuming that the frequency of the turbulent fluctuations is characterized by the frequency of the linear waves supported by the plasma, we evaluate the validity of the Taylor hypothesis for the linear kinetic wave modes in the weakly collisional solar wind…
2014