arXiv subjects

M. Maksimovic

Publications and source records attributed to M. Maksimovic.

At least 19 recordsLinked to original sources

arXiv2026

Modelling spacecraft-emitted electrons measured by SWA-EAS experiment on board Solar Orbiter mission

Thermal electron measurements in space plasmas typically suffer at low energies from spacecraft emissions of photo- and secondary electrons and from charging of the spacecraft body. We examine these effects by use of numerical simulations in the context of electron measurements acquired by the Electron Analyser System (SWA-EAS) on board the Solar Orbiter mission. We employed the Spacecraft Plasma Interaction Software to model the interaction of the Solar Orbiter spacecraft with solar wind plasma and we implemented a virtual detector to simulate the measured electron energy spectra as observed in situ by the SWA-EAS experiment. Numerical simulations were set according to the measured plasma conditions at 0.3~AU. We derived the simulated electron energy spectra as detected by the virtual SWA-EAS experiment for different electron populations and compared these with both the initial plasma conditions and the corresponding real SWA-EAS data samples. We found qualitative agreement between the simulated and real data observed in situ by the SWA-EAS detector. Contrary to other space missions, the contamination by cold electrons emitted from the spacecraft is seen well above the spacecraft potential energy threshold. A detailed analysis of the simulated electron energy spectra demonstrates that contamination above the threshold is a result of cold electron fluxes emitted from distant spacecraft surfaces. The relative position of the break in the simulated spectrum with respect to the spacecraft potential slightly deviates from that in the real observations. This may indicate that the real potential of the SWA-EAS detector with respect to ambient plasma differs from the spacecraft potential value measured on board. The overall contamination is shown to be composed of emissions from a number of different sources and their relative contribution varies with the ambient plasma conditions.

astro-ph.IM↗

arXiv2025

CoSEE-Cat: A Comprehensive Solar Energetic Electron event Catalogue obtained from combined in situ and remote-sensing observations from Solar Orbiter -- Catalogue description and first statistical results

(abridged) The acceleration of particles at the Sun and their propagation through interplanetary space are key topics in heliophysics. Specifically, solar energetic electrons (SEEs) measured in situ can be linked to solar flares and coronal mass ejections (CMEs), which can be observed remotely in radio, optical, UV and X-rays. Solar Orbiter, equipped with a wide range of remote-sensing and in situ detectors, provides an excellent opportunity to investigate SEEs and their solar origin from the inner heliosphere. The Comprehensive Solar Energetic Electron event Catalogue (CoSEE-Cat) provides details for all SEE events measured in situ by Solar Orbiter, as well as associated flares, CMEs, and radio bursts. The catalogue contains key parameters of the SEEs, as derived from the Energetic Particle Detector (EPD), complemented with basic parameters of associated X-ray flares provided by STIX, information on eruptive phenomena seen by EUI, characteristics of type III radio bursts observed by RPW, and indications of CME observed by Metis and SoloHI. The conditions in interplanetary space were characterised using SWA and MAG measurements. Finally, data-driven modelling with the Magnetic Connectivity Tool provided an independent estimate of the solar source position of the SEEs. The first data release contains 303 SEE events observed from November 2020 until the end of 2022. In this paper, we describe the catalogue and provide a first statistical analysis. Preliminary results support the flare-related origin of events with an impulsive ion composition and the association of gradual events with extended structures such as CME-driven shocks or erupting flux ropes. We also show that the commonly observed delays of the solar release times of the SEEs relative to the associated X-ray flares and type III radio bursts are at least partially due to propagation effects.

astro-ph.SR↗

arXiv2025

Generalized Two Thermal Regimes Approach : Bipoly Fluid Modeling

The isopoly bi-fluid approach assumes an isothermal evolution of the solar wind near the Sun up to the radial distance riso, followed by a polytropic evolution constrained by the observed polytropic indices. This approach provides a more accurate model of the interplanetary properties of the solar wind (u, n, Tp, Te) and their radial evolution (Dakeyo et al. 2022, 2024). In this article, we present an improvement of the isopoly approach by considering a generalized two thermal regime approach, embedding two distinct polytropic evolutions, the "bipoly" modeling. To demonstrate the capability of the approach, the models are fitted to both interplanetary and coronal observations, all classified by wind speed population in the spirit of Maksimovic et al. (2020). The set of observations used as constraints are coronal temperatures inferred from charge-state ratio observations from Solar Orbiter, and interplanetary measurements from Helios and Parker Solar Probe. The relaxation of the isothermal criteria in the near-Sun region permits to significantly improve the fast wind acceleration for low coronal temperature conditions. In summary, the new model matches closely the observational constraints: the coronal temperature and the radial evolution of the wind properties (u, n, Tp, Te) in the interplanetary medium, and this for all the wind speed populations.

astro-ph.SR↗

arXiv2024

An Overview of Solar Orbiter Observations of Interplanetary Shocks in Solar Cycle 25

Interplanetary shocks are fundamental constituents of the heliosphere, where they form as a result of solar activity. We use previously unavailable measurements of interplanetary shocks in the inner heliosphere provided by Solar Orbiter, and present a survey of the first 100 shocks observed in situ at different heliocentric distances during the rising phase of solar cycle 25. The fundamental shock parameters (shock normals, shock normal angles, shock speeds, compression ratios, Mach numbers) have been estimated and studied as a function of heliocentric distance, revealing a rich scenario of configurations. Comparison with large surveys of shocks at 1~au show that shocks in the quasi-parallel regime and with high speed are more commonly observed in the inner heliosphere. The wave environment of the shocks has also been addressed, with about 50\% of the events exhibiting clear shock-induced upstream fluctuations. We characterize energetic particle responses to the passage of IP shocks at different energies, often revealing complex features arising from the interaction between IP shocks and pre-existing fluctuations, including solar wind structures being processed upon shock crossing. Finally, we give details and guidance on the access use of the present survey, available on the EU-project ``solar energetic particle analysis platform for the inner heliosphere'' (SERPENTINE) website. The algorithm used to identify shocks in large datasets, now publicly available, is also described.

astro-ph.SR↗

arXiv2024

Testing the flux tube expansion factor -- solar wind speed relation with Solar Orbiter data

The properties of the solar wind measured in-situ in the heliosphere are largely controlled by energy deposition in the solar. Previous studies have shown that long duration and large scale magnetic structures show an inverse relation between the solar wind velocity measured in situ near 1 au and the expansion factor of the magnetic flux tubes in the solar atmosphere. We exploit Solar Orbiter data in conjunction with the Potential Field Source Surface (PFSS) coronal model, and the solar wind trajectory to evaluate the flux expansion factor - speed relation at the solar "source surface" at rss. We find a statistically weak anti-correlation between the in-situ bulk velocity and the coronal expansion factor, for about 1.5 years of solar data. Classification of the data by source latitude reveals different levels of anticorrelation. We show the existence of fast solar wind that originates in strong magnetic field regions at low latitudes and undergoes large expansion factor. We provide evidence that such winds become supersonic during the super radial expansion (below rss), and are theoretically governed by a positive correlation v-f. We find that faster winds on average have a flux tube expansion at a larger radius than slower winds. An anticorrelation between solar wind speed and expansion factor is present for solar winds originating in high latitude structures in solar minimum activity, typically associated with coronal hole-like structures, but this cannot be generalized to lower latitude sources. Therefore, the value of the expansion factor alone cannot be used to predict the solar wind speed. Other parameters, such as the height at which the expansion gradient is the strongest must also be taken into account.

astro-ph.SR↗

arXiv2024

Quantifying the diffusion of suprathermal electrons by whistler waves between 0.2 and 1 AU with Solar Orbiter and Parker Solar Probe

The evolution of the solar wind electron distribution function with heliocentric distance exhibits different features that are still unexplained, in particular, the increase of the Strahl pitch angle width. Wave-particle interactions between electrons and whistler waves are often proposed to explain these phenomena. We aim at quantifying the effect of whistler waves on suprathermal electrons as a function of heliocentric distance. We first perform a statistical analysis of whistler waves (occurrence and properties) observed by Solar Orbiter and Parker Solar Probe between 0.2 and 1 AU. The wave characteristics are then used to compute the diffusion coefficients in the framework of quasi-linear theory. These coefficients are integrated in order to deduce the overall effect of whistler waves on electrons along their propagation. 110,000 whistler wave packets are detected and characterized in the plasma frame. Most waves are aligned with the magnetic field and only about 0.5% of them have a propagation angle greater than 45°. Beyond 0.3 AU, almost exclusively anti-sunward waves (some of them are found sunward but are within switchbacks with a change of sign of the radial component of the background magnetic) are observed. These waves are therefore Strahl-aligned and not counter-streaming. At 0.2 AU we find both Strahl-aligned and counter-streaming waves. Beyond 0.3 AU, the integrated diffusion coefficients show that the observed waves can explain the measured Strahl pitch angle evolution and are effective in isotropizing the halo. Strahl diffusion is mainly due to whistler waves with an angle of propagation between 15° and 45°. Near 0.2 AU, counter-streaming whistler waves can diffuse the Strahl electrons more efficiently than the Strahl-aligned waves by two orders of magnitude.

astro-ph.SR↗

arXiv2023

Total Electron Temperature Derived from Quasi-Thermal Noise Spectroscopy In the Pristine Solar Wind: Parker Solar Probe Observations

The Quasi-thermal noise (QTN) technique is a reliable tool to yield accurate measurements of the electron parameters in the solar wind. We apply this method on Parker Solar Probe (PSP) observations to derive the total electron temperature ($T_e$) from the linear fit of the high-frequency part of the QTN spectra acquired by the RFS/FIELDS instrument, and present a combination of 12-day period of observations around each perihelion from Encounter One (E01) to Ten (E10) (with E08 not included) with the heliocentric distance varying from about 13 to 60 solar radii ($R_\odot{}$). We find that the total electron temperature decreases with the distance as $\sim$$R^{-0.66}$, which is much slower than adiabatic. The extrapolated $T_e$ based on PSP observations is consistent with the exospheric solar wind model prediction at $\sim$10 $R_\odot{}$, Helios observations at $\sim$0.3 AU and Wind observations at 1 AU. Also, $T_e$, extrapolated back to 10 $R_\odot{}$, is almost the same as the strahl electron temperature $T_s$ (measured by SPAN-E) which is considered to be closely related to or even almost equal to the coronal electron temperature. Furthermore, the radial $T_e$ profiles in the slower solar wind (or flux tube with larger mass flux) are steeper than those in the faster solar wind (or flux tube with smaller mass flux). More pronounced anticorrelated $V_p$-$T_e$ is observed when the solar wind is slower and closer to the Sun.

astro-ph.SR↗

arXiv2023

The 17 April 2021 widespread solar energetic particle event

Context. A solar eruption on 17 April 2021 produced a widespread Solar Energetic Particle (SEP) event that was observed by five longitudinally well-separated observers in the inner heliosphere at heliocentric distances of 0.42 to 1 au: BepiColombo, Parker Solar Probe, Solar Orbiter, STEREO A, and near-Earth spacecraft. The event produced relativistic electrons and protons. It was associated with a long-lasting solar hard X-ray flare and a medium fast Coronal Mass Ejection (CME) with a speed of 880 km/s driving a shock, an EUV wave as well as long-lasting radio burst activity showing four distinct type III burst. Methods. A multi-spacecraft analysis of remote-sensing and in-situ observations is applied to attribute the SEP observations at the different locations to the various potential source regions at the Sun. An ENLIL simulation is used to characterize the interplanetary state and its role for the energetic particle transport. The magnetic connection between each spacecraft and the Sun is determined. Based on a reconstruction of the coronal shock front we determine the times when the shock establishes magnetic connections with the different observers. Radio observations are used to characterize the directivity of the four main injection episodes, which are then employed in a 2D SEP transport simulation. Results. Timing analysis of the inferred SEP solar injection suggests different source processes being important for the electron and the proton event. Comparison among the characteristics and timing of the potential particle sources, such as the CME-driven shock or the flare, suggests a stronger shock contribution for the proton event and a more likely flare-related source of the electron event. Conclusions. We find that in this event an important ingredient for the wide SEP spread was the wide longitudinal range of about 110 degrees covered by distinct SEP injections.

astro-ph.SR↗

arXiv2022

The Radial Evolution of the Solar Wind as Organized by Electron Distribution Parameters

We utilize observations from the Parker Solar Probe (PSP) to study the radial evolution of the solar wind in the inner heliosphere. We analyze electron velocity distribution functions observed by the Solar Wind Electrons, Alphas, and Protons suite to estimate the coronal electron temperature and the local electric potential in the solar wind. From the latter value and the local flow speed, we compute the asymptotic solar wind speed. We group the PSP observations by asymptotic speed, and characterize the radial evolution of the wind speed, electron temperature, and electric potential within each group. In agreement with previous work, we find that the electron temperature (both local and coronal) and the electric potential are anti-correlated with wind speed. This implies that the electron thermal pressure and the associated electric field can provide more net acceleration in the slow wind than in the fast wind. We then utilize the inferred coronal temperature and the extrapolated electric + gravitational potential to show that both electric field driven exospheric models and the equivalent thermally driven hydrodynamic models can explain the entire observed speed of the slowest solar wind streams. On the other hand, neither class of model can explain the observed speed of the faster solar wind streams, which thus require additional acceleration mechanisms.

astro-ph.SR↗

arXiv2021

Whistler waves observed by Solar Orbiter / RPW between 0.5 AU and 1 AU

The goal of our study is to detect and characterize the electromagnetic waves that can modify the electron distribution functions, with a special attention to whistler waves. We analyse in details the electric and magnetic field fluctuations observed by the Solar Orbiter spacecraft during its first orbit around the Sun between 0.5 and 1 AU. Using data of the Search Coil Magnetometer and electric antenna, both parts of the Radio and Plasma Waves (RPW) instrumental suite, we detect the electromagnetic waves with frequencies above 3 Hz and determine the statistical distribution of their amplitudes, frequencies, polarization and k-vector as a function of distance. We also discuss relevant instrumental issues regarding the phase between the electric and magnetic measurements and the effective length of the electric antenna. An overwhelming majority of the observed waves are right hand circularly polarized in the solar wind frame and identified as outward propagating and quasi parallel whistler waves. Their occurrence rate increases by a least a factor two from 1 AU to 0.5 AU. These results are consistent with the regulation of the heat flux by the whistler heat flux instability. Near 0.5 AU, whistler waves are found to be more field-aligned and to have smaller normalized frequency ($f/f_{ce}$), larger amplitude, and larger bandwidth than at 1 AU.

astro-ph.SR↗

arXiv2021

Simulations of radio-wave anisotropic scattering to interpret type III radio bursts measurements by Solar Orbiter, Parker Solar Probe, STEREO and Wind

We use multi-spacecraft observations of invididual type III radio bursts in order to calculate the directivity of the radio emission, to be compared to the results of ray-tracing simulations of the radio-wave propagation and probe the plasma properties of the inner heliosphere. Ray-tracing simulations of radio-wave propagation with anisotropic scattering on density inhomogeneities are used to study the directivity of radio emissions. Simultaneous observations of type III radio bursts by four widely-separated spacecraft are used to calculate the directivity and position of the radio sources. The shape of the directivity pattern deduced for individual events is compared to the directivity pattern resulting from the ray-tracing simulations. We show that simultaneous observations of type radio III bursts by 4 different probes provide the opportunity to estimate the radio source positions and the directivity of the radio emission. The shape of the directivity varies from one event to another, and is consistent with anisotropic scattering of the radio-waves.

astro-ph.SR↗

arXiv2021

Magnetic reconnection as a mechanism to produce multiple protonpopulations and beams locally in the solar wind

Context. Spacecraft observations early revealed frequent multiple proton populations in the solar wind. Decades of research on their origin have focused on processes such as magnetic reconnection in the low corona and wave-particle interactions in the corona and locally in the solar wind.Aims.This study aims to highlight that multiple proton populations and beams are also produced by magnetic reconnection occurring locally in the solar wind. Methods. We use high resolution Solar Orbiter proton velocity distribution function measurements, complemented by electron and magnetic field data, to analyze the association of multiple proton populations and beams with magnetic reconnection during a period of slow Alfvénic solar wind on 16 July 2020. Results. At least 6 reconnecting current sheets with associated multiple proton populations and beams, including a case of magnetic reconnection at a switchback boundary, are found during this day. This represents 2% of the measured distribution functions. We discuss how this proportion may be underestimated, and how it may depend on solar wind type and distance from the Sun. Conclusions. Although suggesting a likely small contribution, but which remains to be quantitatively assessed, Solar Orbiter observations show that magnetic reconnection must be considered as one of the mechanisms that produce multiple proton populations and beams locally in the solar wind.

astro-ph.SR↗

arXiv2021

Solar Orbiter/RPW antenna calibration in the radio domain and its application to type III burst observations

In order to allow for a comparison with the measurements from other antenna systems, the voltage power spectral density measured by the Radio and Plasma waves receiver (RPW) on board Solar Orbiter needs to be converted into physical quantities that depend on the intrinsic properties of the radiation itself.The main goal of this study is to perform a calibration of the RPW dipole antenna system that allows for the conversion of the voltage power spectral density measured at the receiver's input into the incoming flux density. We used space observations from the Thermal Noise Receiver (TNR) and the High Frequency Receiver (HFR) to perform the calibration of the RPW dipole antenna system. Observations of type III bursts by the Wind spacecraft are used to obtain a reference radio flux density for cross-calibrating the RPW dipole antennas. The analysis of a large sample of HFR observations (over about ten months), carried out jointly with an analysis of TNR-HFR data and prior to the antennas' deployment, allowed us to estimate the reference system noise of the TNR-HFR receivers. We obtained the effective length of the RPW dipoles and the reference system noise of TNR-HFR in space, where the antennas and pre-amplifiers are embedded in the solar wind plasma. The obtained $l_{eff}$ values are in agreement with the simulation and measurements performed on the ground. By investigating the radio flux intensities of 35 type III bursts simultaneously observed by Solar Orbiter and Wind, we found that while the scaling of the decay time as a function of the frequency is the same for the Waves and RPW instruments, their median values are higher for the former. This provides the first observational evidence that Type III radio waves still undergo density scattering, even when they propagate from the source, in a medium with a plasma frequency that is well below their own emission frequency.

astro-ph.SR↗

arXiv2021

The Long Period of 3He-rich Solar Energetic Particles Measured by Solar Orbiter on 2020 November 17-23

We report observations of a relatively long period of 3He-rich solar energetic particles (SEPs) measured by Solar Orbiter. The period consists of several well-resolved ion injections. The high-resolution STEREO-A imaging observations reveal that the injections coincide with EUV jets/brightenings near the east limb, not far from the nominal magnetic connection of Solar Orbiter. The jets originated in two adjacent, large, and complex active regions as observed by the Solar Dynamics Observatory when the regions rotated to the Earth's view. It appears that the sustained ion injections were related to the complex configuration of the sunspot group and the long period of 3He-rich SEPs to the longitudinal extent covered by the group during the analyzed time period.

astro-ph.SR↗

arXiv2021

First-year ion-acoustic wave observations in the solar wind by the RPW/TDS instrument onboard Solar Orbiter

Electric field measurements of the Time Domain Sampler (TDS) receiver, part of the Radio and Plasma Waves (RPW) instrument on board Solar Orbiter, often exhibit very intense broadband wave emissions at frequencies below 20~kHz in the spacecraft frame. In this paper, we present a year-long study of electrostatic fluctuations observed in the solar wind at an interval of heliocentric distances from 0.5 to 1~AU. The RPW/TDS observations provide a nearly continuous data set for a statistical study of intense waves below the local plasma frequency. The on-board and continuously collected and processed properties of waveform snapshots allow for the mapping plasma waves at frequencies between 200~Hz and 20~kHz. We used the triggered waveform snapshots and a Doppler-shifted solution of the dispersion relation for wave mode identification in order to carry out a detailed spectral and polarization analysis. Electrostatic ion-acoustic waves are the common wave emissions observed between the local electron and proton plasma frequency in the soler wind. The occurrence rate of ion-acoustic waves peaks around perihelion at distances of 0.5~AU and decreases with increasing distances, with only a few waves detected per day at 0.9~AU. Waves are more likely to be observed when the local proton moments and magnetic field are highly variable. A more detailed analysis of more than 10000 triggered waveform snapshots shows the mean wave frequency at about 3 kHz and wave amplitude about 2.5 mV/m. The wave amplitude varies as 1/R^(1.38) with the heliocentric distance. The relative phase distribution between two components of the E-field shows a mostly linear wave polarization. Electric field fluctuations are closely aligned with the directions of the ambient field lines. Only a small number (3%) of ion-acoustic waves are observed at larger magnetic discontinuities.

physics.space-ph↗

arXiv2021

Density Fluctuations Associated with Turbulence and Waves: First Observations by Solar Orbiter

We use the plasma density based on measurements of the probe-to-spacecraft potential in combination with magnetic field measurements by MAG to study fields and density fluctuations in the solar wind observed by Solar Orbiter during the first perihelion encounter ($\sim$0.5~AU away from the Sun). In particular we use the polarization of the wave magnetic field, the phase between the compressible magnetic field and density fluctuations and the compressibility ratio (the ratio of the normalized density fluctuations to the normalized compressible fluctuations of B) to characterize the observed waves and turbulence. We find that the density fluctuations are out-of-phase with the compressible component of magnetic fluctuations for intervals of turbulence, while they are in phase for the circular-polarized waves around the proton cyclotron frequency. We analyze in detail two specific events with simultaneous presence of left- and right-handed waves at different frequencies. We compare observed wave properties to a prediction of the three-fluid (electrons, protons and alphas) model. We find a limit on the observed wavenumbers, $10^{-6} < k < 7 \times 10^{-6}$~m$^{-1}$, which corresponds to wavelength $7 \times 10^6 >λ> 10^6$~m. We conclude that most likely both the left- and right-handed waves correspond to the low-wavenumber part (close to the cut-off at $Ω_{c\mathrm{He}++}$) proton-band electromagnetic ion cyclotron (left-handed wave in the plasma frame confined to the frequency range $Ω_{c\mathrm{He}++} < ω< Ω_{c\mathrm{H}+}$) waves propagating in the outwards and inwards directions respectively. The fact that both wave polarizations are observed at the same time and the identified wave mode has a low group velocity suggests that the double-banded events occur in the source regions of the waves.

physics.space-ph↗

arXiv2021

Statistical study of electron density turbulence and ion-cyclotron waves in the inner heliosphere: Solar Orbiter observations

The recently released spacecraft potential measured by the RPW instrument on-board Solar Orbiter has been used to estimate the solar wind electron density in the inner heliosphere. Solar-wind electron density measured during June 2020 has been analysed to obtain a thorough characterization of the turbulence and intermittency properties of the fluctuations. Magnetic field data have been used to describe the presence of ion-scale waves. Selected intervals have been extracted to study and quantify the properties of turbulence. The Empirical Mode Decomposition has been used to obtain the generalized marginal Hilbert spectrum, equivalent to the structure functions analysis, and additionally reducing issues typical of non-stationary, short time series. The presence of waves was quantitatively determined introducing a parameter describing the time-dependent, frequency-filtered wave power. A well defined inertial range with power-law scaling has been found almost everywhere. However, the Kolmogorov scaling and the typical intermittency effects are only present in part of the samples. Other intervals have shallower spectra and more irregular intermittency, not described by models of turbulence. These are observed predominantly during intervals of enhanced ion frequency wave activity. Comparisons with compressible magnetic field intermittency (from the MAG instrument) and with an estimate of the solar wind velocity (using electric and magnetic field) are also provided to give general context and help determine the cause for the anomalous fluctuations.

physics.space-ph↗

arXiv2021

Signatures of coronal hole substructure in the solar wind: combined Solar Orbiter remote sensing and in situ measurements

Context. The Sun's complex corona is the source of the solar wind and interplanetary magnetic field. While the large scale morphology is well understood, the impact of variations in coronal properties on the scale of a few degrees on properties of the interplanetary medium is not known. Solar Orbiter, carrying both remote sensing and in situ instruments into the inner solar system, is intended to make these connections better than ever before. Aims. We combine remote sensing and in situ measurements from Solar Orbiter's first perihelion at 0.5 AU to study the fine scale structure of the solar wind from the equatorward edge of a polar coronal hole with the aim of identifying characteristics of the corona which can explain the in situ variations. Methods. We use in situ measurements of the magnetic field, density and solar wind speed to identify structures on scales of hours at the spacecraft. Using Potential Field Source Surface mapping we estimate the source locations of the measured solar wind as a function of time and use EUI images to characterise these solar sources. Results. We identify small scale stream interactions in the solar wind with compressed magnetic field and density along with speed variations which are associated with corrugations in the edge of the coronal hole on scales of several degrees, demonstrating that fine scale coronal structure can directly influence solar wind properties and drive variations within individual streams. Conclusions. This early analysis already demonstrates the power of Solar Orbiter's combined remote sensing and in situ payload and shows that with future, closer perihelia it will be possible dramatically to improve our knowledge of the coronal sources of fine scale solar wind structure, which is important both for understanding the phenomena driving the solar wind and predicting its impacts at the Earth and elsewhere.

astro-ph.SR↗