First Results from Solar Orbiter’s Energetic Particle Detector

Mapping Intimacies ◽

10.5194/egusphere-egu21-15792 ◽

2021 ◽

Author(s):

Javier Rodriguez-Pacheco ◽

Keyword(s):

Energetic Particle ◽

Wide Energy Range ◽

High Temporal Resolution ◽

The Sun ◽

Particle Detector ◽

First Results ◽

Wide Energy ◽

Spatio Temporal ◽

Inner Heliosphere

In this presentation, we will show the first measurements performed by EPD since the end of the commissioning phase until the latest results obtained. During these months EPD has been scanning the inner heliosphere at different heliocentric distances and heliolongitues allowing - together with other spacecraft - to investigate the&#160;spatio-temporal behavior of the particle populations in the inner&#160;heliosphere during solar minimum conditions. Solar Orbiter was launched from Cape Canaveral on February 10th, 2020, thus beginning the journey to its encounter with the Sun. Solar Orbiter carries ten scientific instruments, six remote sensing and four in situ, that will allow the mission main goal: how the Sun creates and controls the heliosphere. Among the in situ instruments, the Energetic Particle Detector (EPD) measures electrons, protons and heavy ions with high temporal resolution over a wide energy range, from suprathermal energies up to several hundreds of MeV/nucleon.

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The Energetic Particle Detector

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935287 ◽

2020 ◽

Vol 642 ◽

pp. A7 ◽

Cited By ~ 10

Author(s):

J. Rodríguez-Pacheco ◽

R. F. Wimmer-Schweingruber ◽

G. M. Mason ◽

G. C. Ho ◽

S. Sánchez-Prieto ◽

...

Keyword(s):

Energy Range ◽

Energetic Particle ◽

Ecliptic Plane ◽

High Energy ◽

Energetic Particles ◽

Wide Energy Range ◽

High Temporal Resolution ◽

Particle Detector ◽

Heliographic Latitude ◽

Inner Heliosphere

After decades of observations of solar energetic particles from space-based observatories, relevant questions on particle injection, transport, and acceleration remain open. To address these scientific topics, accurate measurements of the particle properties in the inner heliosphere are needed. In this paper we describe the Energetic Particle Detector (EPD), an instrument suite that is part of the scientific payload aboard the Solar Orbiter mission. Solar Orbiter will approach the Sun as close as 0.28 au and will provide extra-ecliptic measurements beyond ∼30° heliographic latitude during the later stages of the mission. The EPD will measure electrons, protons, and heavy ions with high temporal resolution over a wide energy range, from suprathermal energies up to several hundreds of megaelectronvolts/nucleons. For this purpose, EPD is composed of four units: the SupraThermal Electrons and Protons (STEP), the Electron Proton Telescope (EPT), the Suprathermal Ion Spectrograph (SIS), and the High-Energy Telescope (HET) plus the Instrument Control Unit that serves as power and data interface with the spacecraft. The low-energy population of electrons and ions will be covered by STEP and EPT, while the high-energy range will be measured by HET. Elemental and isotopic ion composition measurements will be performed by SIS and HET, allowing full particle identification from a few kiloelectronvolts up to several hundreds of megaelectronvolts/nucleons. Angular information will be provided by the separate look directions from different sensor heads, on the ecliptic plane along the Parker spiral magnetic field both forward and backwards, and out of the ecliptic plane observing both northern and southern hemispheres. The unparalleled observations of EPD will provide key insights into long-open and crucial questions about the processes that govern energetic particles in the inner heliosphere.

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Large-scale electron solar wind parameters of the inner heliosphere with Parker Solar Probe/FIELDS

10.5194/egusphere-egu2020-18573 ◽

2020 ◽

Author(s):

Karine Issautier ◽

Mingzhe Liu ◽

Michel Moncuquet ◽

Nicole Meyer-Vernet ◽

Milan Maksimovic ◽

...

Keyword(s):

Solar Wind ◽

Large Scale ◽

Statistical Study ◽

Solar Wind Speed ◽

The Sun ◽

Solar Wind Parameters ◽

Power Law Index ◽

Probe Mission ◽

Inner Heliosphere

We present in situ properties of electron density and temperature in the inner heliosphere obtained during the three first solar encounters at 35 solar radii of the Parker Solar Probe mission. These preliminary results, recently shown by Moncuquet et al., ApJS, 2020, are obtained from the analysis of the plasma quasi-thermal noise (QTN) spectrum measured by the radio RFS/FIELDS instrument along the trajectories extending between 0.5 and 0.17 UA from the Sun, revealing different states of the emerging solar wind, five months apart. The temperature of the weakly collisional core population varies radially with a power law index of about -0.8, much slower than adiabatic, whereas the temperature of the supra-thermal population exhibits a much flatter radial variation, as expected from its nearly collisionless state. These measured temperatures are close to extrapolations towards the Sun of Helios measurements.We also present a statistical study from these in situ electron solar wind parameters, deduced by QTN spectroscopy, and compare the data to other onboard measurements. In addition, we focus on the large-scale solar wind properties. In particular, from the invariance of the energy flux, a direct relation between the solar wind speed and its density can be deduced, as we have already obtained based on Wind continuous in situ measurements (Le Chat et al., Solar Phys., 2012). We study this anti-correlation during the three first solar encounters of PSP.

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Energetic Particle Environment near the Sun from Parker Solar Probe

10.5194/egusphere-egu2020-6063 ◽

2020 ◽

Author(s):

Nathan Schwadron ◽

Keyword(s):

Energetic Particle ◽

Energetic Particles ◽

Solar Energetic Particles ◽

Radiation Environment ◽

The Sun ◽

Particle Radiation ◽

Integrated Science ◽

Direct Observations ◽

Interaction Regions ◽

Inner Heliosphere

NASA&#8217;s Parker Solar Probe (PSP) mission recently plunged through the inner heliosphere to perihelia at ~24 million km (~35 solar radii), much closer to the Sun than any prior human made object. Onboard PSP, the Integrated Science Investigation of the Sun (IS&#664;IS) instrument suite made groundbreaking measurements of solar energetic particles (SEPs). Here we discuss the near-Sun energetic particle radiation environment over PSP&#8217;s first two orbits, which reveal where and how energetic particles are energized and transported. We find a great variety of energetic particle events accelerated both locally and remotely. These include co-rotating interaction regions (CIRs), &#8220;impulsive&#8221; SEP events driven by acceleration near the Sun, and events related to Coronal Mass Ejections (CMEs). These IS&#664;IS observations made so close to the Sun provide critical information for investigating the near-Sun transport and energization of solar energetic particles that was difficult to resolve from prior observations. We discuss the physics of particle acceleration and transport in the context of various theories and models that have been developed over the past decades. This study marks a major milestone with humanity&#8217;s reconnaissance of the near-Sun environment and provides the first direct observations of the energetic particle radiation environment in the region just above the corona.

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Variable Ion Compositions of Solar Energetic Particle Events in the Inner Heliosphere: A Field Line Braiding Model with Compound Injections

The Astrophysical Journal ◽

10.3847/1538-4357/ac3233 ◽

2022 ◽

Vol 924 (1) ◽

pp. 22

Author(s):

Fan Guo ◽

Lulu Zhao ◽

Christina M. S. Cohen ◽

Joe Giacalone ◽

R. A. Leske ◽

...

Keyword(s):

Magnetic Field ◽

Energetic Particle ◽

Radial Distance ◽

Solar Energetic Particle ◽

The Sun ◽

Ion Composition ◽

Source Regions ◽

Solar Energetic Particle Events ◽

Composition Ratios ◽

Inner Heliosphere

Abstract We propose a model for interpreting highly variable ion composition ratios in solar energetic particle (SEP) events recently observed by the Parker Solar Probe (PSP) at 0.3–0.45 au. We use numerical simulations to calculate SEP propagation in a turbulent interplanetary magnetic field with a Kolmogorov power spectrum from large scales down to the gyration scale of energetic particles. We show that when the source regions of different species are offset by a distance comparable to the size of the source regions, the observed energetic particle composition He/H can be strongly variable over more than two orders of magnitude, even if the source ratio is at the nominal value. Assuming a 3He/4He source ratio of 10% in impulsive 3He-rich events and the same spatial offset of the source regions, the 3He/4He ratio at observation sites also vary considerably. The variability of the ion composition ratios depends on the radial distance, which can be tested by observations made at different radial locations. We discuss the implications of these results on the variability of ion composition of impulsive events and on further PSP and Solar Orbiter observations close to the Sun.

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Radial Evolution of Coronal Mass Ejections in the Inner Heliosphere: Catalog and Analysis

10.5194/egusphere-egu2020-4009 ◽

2020 ◽

Author(s):

Tarik Salman ◽

Reka Winslow ◽

Noé Lugaz

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Magnetic Field Strength ◽

Coronal Mass Ejections ◽

The Sun ◽

Maximum Magnetic Field ◽

Venus Express ◽

Radial Evolution ◽

Inner Heliosphere

Our knowledge of the properties of Coronal Mass Ejections (CMEs) in the inner heliosphere is constrained by the relative lack of plasma observations between the Sun and 1 AU. In this work, we present a comprehensive catalog of 47 CMEs measured in situ measurements by two or more radially aligned spacecraft (MESSENGER, Venus Express, STEREO, and Wind/ACE). We estimate the CME impact speeds at Mercury and Venus using a drag-based model and present an average propagation profile of CMEs (speed and deceleration/acceleration) in the inner heliosphere. We find that CME deceleration continues past Mercury's orbit but most of the deceleration occurs between the Sun and Mercury. We examine the exponential decrease of the maximum magnetic field strength in the CME with heliocentric distance using two approaches: a modified statistical method and analysis from individual conjunction events. Findings from both the approaches are on average consistent with previous studies but show significant event-to-event variability. We also find the expansion of the CME sheath to be well fit by a linear function. However, we observe the average sheath duration and its increase to be fairly independent of the initial CME speed, contradicting commonly held knowledge that slower CMEs drive larger sheaths. We also present an analysis of the 3 November 2011 CME observed in a longitudinal conjunction between MESSENGER, Venus Express, and STEREO-B focusing on the expansion of the CME and its correlation with the exponential fall-off of the maximum magnetic field strength in the ejecta.

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First Results From SPICE EUV Spectrometer on Solar Orbiter

10.5194/egusphere-egu21-5577 ◽

2021 ◽

Author(s):

Andrzej Fludra ◽

Keyword(s):

Neutral Hydrogen ◽

Spectral Lines ◽

Average Intensity ◽

The Sun ◽

Imaging Spectrometer ◽

Quiet Sun ◽

First Results ◽

Disk Centre ◽

Wide Slit

SPICE (Spectral Imaging of Coronal Environment) is an EUV imaging spectrometer onboard Solar Orbiter. SPICE observes the Sun in two wavelength bands: 69.6-79.4 nm and 96.6-105.1 nm and is capable of recording full spectra in these bands with exposures as short as 1s. SPICE can measure spectra from the disk and low corona, and records all spectral lines simultaneously, using one of three narrow slits: 2&#8221;x11&#8217;, 4&#8217;&#8217;x11&#8217;, 6&#8217;&#8217;x11&#8217;, or a wide slit 30&#8217;&#8217;x14&#8217;. The primary mirror can be scanned in a direction perpendicular to the slit, allowing raster images of up to 16&#8217; in size.The first SPICE data were taken during the instrument commissioning carried out by the RAL Space team between 2020 April 21 and 2020 June 14, and at the first Solar Orbiter perihelion at 0.52AU between June 16-21. &#160;We give examples of full spectra from the quiet Sun near disk centre and provide a list of key spectral lines from neutral hydrogen and ions of carbon, oxygen, nitrogen, neon, sulphur and magnesium. These lines cover the temperature range between 10,000 K and 1 million K (10MK in flares), providing slices of the Sun&#8217;s atmosphere in narrow temperature intervals. We show examples of raster images in several strong lines, obtained with different slits and a range of exposure times between 5s and 180s.We have found several unusually bright, compact structures (named &#8220;beacons&#8221;) in the quiet Sun network, with extreme intensities up to 22 times greater than the average intensity across the image. The lifetimes of these sources are longer than 1 hour. We will derive plasma velocities in the beacon area, and co-align the SPICE rasters with the SDO/AIA 304 and 171 images and the HMI magnetic field to better understand the origin and properties of beacons.We also show the first above-limb measurements with SPICE in Mg IX, Ne VIII and O VI lines, as obtained when the spacecraft pointed at the limb. Maps of Mg/Ne abundance ratios on disk can be derived and compared with in situ measurements to help confirm the magnetic connection between the spacecraft location and the Sun&#8217;s surface, and locate the sources of the solar wind.

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The New Beamline LISA at ESRF: Performances and Perspectives for Earth and Environmental Sciences

Condensed Matter ◽

10.3390/condmat4010012 ◽

2019 ◽

Vol 4 (1) ◽

pp. 12 ◽

Cited By ~ 6

Author(s):

Alessandro Puri ◽

Giovanni Lepore ◽

Francesco d’Acapito

Keyword(s):

European Synchrotron Radiation Facility ◽

Small Sample ◽

Photon Flux ◽

Wide Energy Range ◽

X Ray ◽

Chemical Treatments ◽

Wide Energy ◽

X Ray Absorption ◽

Raggi X

LISA (Linea Italiana per la Spettroscopia di Assorbimento di raggi X) is the new Italian Collaborating Research Group (CRG) beamline at the European Synchrotron Radiation Facility (ESRF) dedicated to X-ray absorption spectroscopy (XAS). The beamline covers a wide energy range, 4 < E < 90 keV, which offers the possibility for probe the K and L edges of elements that are heavier than Ca. A liquid He/N2 cryostat and a compact furnace are available for measurements in a wide temperature range (10–1000 K), allowing for in situ chemical treatments and measurements under a controlled atmosphere. The sub-millimetric beam size, the high photon flux provided, and the X-ray fluorescence detectors available (HP-Ge, SDD) allow for the study of liquid and highly diluted samples. Trace elements in geological or environmental samples can be analyzed, even for very small sample areas, gaining information on oxidation states and host phases.

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The High Energy Telescope (HET) on the SolarOrbiter Mission: Overview and First Data

10.5194/egusphere-egu21-6776 ◽

2021 ◽

Author(s):

Zigong Xu ◽

Johan L. Freiherr von Forstner ◽

Patrick Kühl ◽

Nils Janitzek ◽

César Martín ◽

...

Keyword(s):

Magnetic Field ◽

Energetic Particle ◽

Cosmic Radiation ◽

Solar Energetic Particle ◽

Cosmic Ray ◽

High Energy ◽

The Sun ◽

Particle Detector ◽

Energy Response ◽

Broad Energy

As part of the Energetic Particle Detector (EPD) suite onboard Solar Orbiter, the High Energy Telescope has been launched on its mission to the Sun on February 9, 2020, and has been measuring energetic particles since it was first switched on about two weeks after launch. Using their double-ended telescopes, the two HET units provide measurements of ions above 7 MeV/nuc and electrons above 300 keV in four viewing directions. HET observed several Solar Energetic Particle (SEPs) events during the cruise phase, including the first one with a broad energy coverage (up to ~100MeV) on 29 Nov 2020. Being the first larger SEP event in a phase of rising solar activity, these measurements have already attracted extensive attention of the community. Apart from the SEPs, the HET can be used to observe the Galactic cosmic radiation (GCR) and its temporal variation. The GCR measurements can be also utilized for the validation of the energy response of HET. The overall spectra observed by HET are as expected, except for calibration issues in some specific energy bins that we are still investigating. Finally, the HET also observed several Forbush Decreases (FD), i.e. cosmic ray decreases caused by CMEs and their embedded magnetic field. Here, the capabilities and data products of HET, as well as first measurements of SEPs, GCR and FDs are presented.&#160;

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Matching high resolution satellite data and flux tower footprints improves their agreement in photosynthesis estimates

10.31223/x5nw55 ◽

2022 ◽

Author(s):

Juwon Kong ◽

Youngryel Ryu ◽

Jiangong Liu ◽

Benjamin Dechant ◽

Camilo Rey-Sanchez ◽

...

Keyword(s):

Temporal Resolution ◽

Near Infrared ◽

Temporal Variations ◽

High Temporal Resolution ◽

Canopy Photosynthesis ◽

Flux Tower ◽

Combining Data ◽

Spatio Temporal ◽

Study Sites

Mapping canopy photosynthesis in both high spatial and temporal resolution is essential for carbon cycle monitoring in heterogeneous areas. However, well established satellites in sun-synchronous orbits such as Sentinel-2, Landsat and MODIS can only provide either high spatial or high temporal resolution but not both. Recently established CubeSat satellite constellations have created an opportunity to overcome this resolution trade-off. In particular, Planet Fusion allows full utilization of the CubeSat data resolution and coverage while maintaining high radiometric quality. In this study, we used the Planet Fusion surface reflectance product to calculate daily, 3-m resolution, gap-free maps of the near-infrared radiation reflected from vegetation (NIRvP). We then evaluated the performance of these NIRvP maps for estimating canopy photosynthesis by comparing with data from a flux tower network in Sacramento-San Joaquin Delta, California, USA. Overall, NIRvP maps captured temporal variations in canopy photosynthesis of individual sites, despite changes in water extent in the wetlands and frequent mowing in the crop fields. When combining data from all sites, however, we found that robust agreement between NIRvP maps and canopy photosynthesis could only be achieved when matching NIRvP maps to the flux tower footprints. In this case of matched footprints, NIRvP maps showed considerably better performance than in situ NIRvP in estimating canopy photosynthesis both for daily sum and data around the time of satellite overpass (R 2 = 0.78 vs. 0.60, for maps vs. in situ for the satellite overpass time case). This difference in performance was mostly due to the higher degree of consistency in slopes of NIRvP -canopy photosynthesis relationships across the study sites for flux tower footprint-matched maps. Our results show the importance of matching satellite observations to the flux tower footprint and demonstrate the potential of CubeSat constellation imagery to monitor canopy photosynthesis remotely at high spatio-temporal resolution.

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