The mesosphere – lower thermosphere (MLT) contains dust particles made of both ice and refractory materials. Since the MLT overlaps with the heights of meteor ablation, it contains small nanometric particles made of cosmic dust material known as meteor smoke. The smoke particles influence the charge balance and ion chemistry and may serve as condensation nuclei for the formation of the ice particles. The ice particles are observed in summer at mid and high latitudes near the mesopause as noctilucent clouds (NLC) or polar mesospheric clouds (PMC). The presence of ice particles in combination with charge interactions, neutral air turbulence and dynamics also leads to specific radar echoes, known as polar mesospheric summer echoes (PMSE). Radar observations of PMSE and PMC/NLC measurements with cameras or lidar are among the few long-term observations around the summer mesopause. PMC/NLC measurements with satellites, cameras or lidar and PMSE measurements with radar indicate there are changes over the last decades. Aside from the ice and the meteoric smoke, space debris is possibly a third source of dust in the MLT that increases over time.The Maxidusty-2 (MXD2) allowed to measure dust, ions and neutrals from a rocket launched from Andoya, Norway (69.1° N, 16° E) on 5 July 2025 around 8:01 am local time. The MXD2 science payload included four dust in-situ detectors, a neutral gas instrument as well as a Faraday rotation experiment and Langmuir probes to measure electron density. Two independent and different instruments collected dust particles. NLC were observed at that time with the Alomar RMR lidar close by. PMSE were observed at the same time with the MAARSY radar close to the launch site and with the EISCAT radar in Ramfjord (69.6° N, 19.2° E) near Tromsoe at about 130 km distance. All in situ instruments recorded science data. The recovery was successful, and analysis of the collected refractory dust samples is ongoing. An overview of the campaign measurements is given. The initial analysis notably shows that the dust instruments measured a signal at the altitude of the NLC but only small signals at the altitude of higher PMSE layer. We discuss the results in terms of dust charging and the link between dust and the other parameters measured.

Abstract. The increase in satellite launches raises the anthropogenic influx of various elements into the Mesosphere and Lower Thermosphere (MLT), comparable to the natural influx caused by meteoric ablation. This study investigates the electrostatic interactions between ice particles and remnants of space debris using a classical electrostatic framework. Aside from the Coulomb interaction, the attractive force between two particles at short distances, arising from polarization, is taken into account. Collision outcomes, the effective velocity regime for collisions, and the subsequent aggregation probability are estimated. Aggregation is limited to a specific range of collision velocities between minimum and maximum values. This range varies depending on factors such as particle size, mass density, and dielectric constant. For most particles, the aggregation velocities range from a few m s-1 to several tens of m s-1, where smaller particles may need significantly higher velocities to form stable aggregates. When considering the collisions of particles in thermal motion, it is found that Al2O3 (due to its greater abundance) and TiO2 (due to its higher dielectric constant), both originating from anthropogenic sources, may dominate in the formation of ice-anthropogenic particle aggregates. In the MLT region, the formation of stable aggregates from the collision of ice with particles from space debris, which one may denote as anthropogenic smoke particles (ASPs), is similar to that from collisions with meteoric smoke particles (MSPs).

Every day, ∼104 kg of planetary and interplanetary material ablates in Earth’s atmosphere, producing meteor trails and depositing metal atoms, ions, and meteoric smoke particles that influence the chemistry and dynamics of the mesosphere–lower thermosphere (MLT) region (80–105 km altitude). These meteoric inputs are linked to interesting phenomena, including noctilucent (polar mesospheric) clouds, polar mesospheric summer echoes (PMSE), and ozone perturbations.In this work, we present volumetric reconstructions of meteor-trail emissions using a regularized, tomography-like inversion applied to multi-station optical observations. The method follows a parameterized forward-model framework previously developed for auroral tomography. The reconstructions are based on simultaneous observations from up to six stations of the ALIS-4D camera network, employing narrow-band filters centered at 427.8 nm, 557.7 nm, and 670.0 nm.To our knowledge, this represents the first application of multi-filter optical tomography to meteoric trails. The resulting three-dimensional emission distributions provide new constraints for meteor ablation simulations and a quantitative reference for studies of excitation, transport, and trail evolution during meteoric events.

This is the summary of findings by ISSI topical team on the molecular and metallic ions in the magnetosphere.Heavy molecular and metallic ions with mass ≥ 27 (Al+, N2+, NO+, O2++, Fe+, Cu+, Ti+, etc) in the magnetosphere provide independent information on the ion sources and entry route to the magnetosphere from traditional four components (H+, He++, He+, O+). There are four ultimate sources of these heavy molecular and metallic ions: the solar wind (high charge-state metallic ions), the ionosphere (mainly molecular ions), the atmospheric metal layers (low charge-state metallic ions and metal-rich molecular ions that ultimately originating from ablation of meteoroids and possibly space debris), and the surface and exosphere go the Moon (low charge-state metallic and molecular ions). The lunar origin low charge-state metallic ions, if separated from the ionospheric origin, give independent information on the entry route into the magnetosphere for ions of much larger gyroradius than the solar wind ions. The atmospheric-origin molecular ions are essential in understanding energization, ionization altitudes, and upward transport in the ionosphere during various ionospheric and magnetospheric conditions. These ions are also important when considering the evolution of the Earth's atmosphere on the geological timescale. So far, we cannot dismiss any of four possible sources with the existing data because only a few terrestrial missions have been equipped with instrumentation dedicated to separate these molecular and metallic ions, within only a limited energy range (cold ions of < 50 eV and energetic ions of ~100 keV or more) and a limited mass range (mainly ≤ 40 amu). This is far too limited to make any quantitative discussion on the very heavy ions in the magnetosphere. Under this circumstance, it is worth to re-examine, using available tools, the existing data from the past and on-going missions, including those not designed for the required mass separation, to search for these ions. We synthesised these patchy observations and combining all sources with updated models. With such knowledge, we re-examined available data and model that actually provided important indications of the sources of these heavy ions and their amounts that have been overlooked to date. Finally, we note the possible future contamination of specific masses by ablated space debris (Al, but also Li, Fe, Ni, Cu, Ti, and Ge) in the coming decades.

NASA’s New Horizons spacecraft is currently exploring the outer solar system and passes the Kuiper Belt. The Student Dust Counter (SDC) onboard New Horizons has measured the flux of interplanetary dust grains throughout nearly the entire mission so far. The observed dust flux around 50 AU at the expected edge of the the Kuipe belt is higher than predicted. A possible explanation could lie in the trajetcries of the dust particles that can be pushed out to large distances by radiation pressure force. We investigate the trajectories of ice particles in the Kuiper belt which are more strongly influenced by radiation pressure when their sizes are reduced, due to mass loss caused by sublimation, solar wind sputtering and photo sputtering. The results suggest that the changing size of the particles may lead to a more stable and confined dust ring in the Solar System's Kuiper Belt.

A radar campaign with High Power Large Aperture (HPLA) radars in northern Norway was performed for the Geminids 2022 meteor shower to make measurements of meteor head echoes. The MAARSY (53.5 MHz), EISCAT VHF (224 MHz), and EISCAT UHF (930 MHz) radars were all operated in a zenith pointing direction. The field-of-views for the EISCAT VHF and EISCAT UHF radars were approximately coincident. A novel meteor head echo processing algorithm was implemented for the EISCAT Manda experiment mode, providing details on the meteor head echo range, Doppler shift, and signal-to-noise ratio (SNR). The occurrence rate of meteor head echo detections for the three different systems were determined as a function of altitude. To investigate the differences in the meteor head echo detection rates, simultaneously detected meteors from the EISCAT VHF and EISCAT UHF were further examined. An altitude dependence of SNR difference between the EISCAT systems was identified and attributed to changes in the atmospheric mean free path. This data was used to determine a plasma density decay rate as a function of r-v, where r is the distance from the center of the meteoroid. v was found to have a value of between 2 to 4 (1/r2 to 1/r4). The meteor head echo detection rate differences between MAARSY, EISCAT VHF, and EISCAT UHF systems can be explained using this plasma density decay rate when the relative radar sensitivities and Rayleigh scattering effects are considered. The results have important implications for the determination of the initial mass of incoming meteoroids and the associated mass-loss rates during ablation. (c) 2025 The Author(s). Published by Elsevier B.V. on behalf of COSPAR. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

Solar Orbiter is equipped with electrical antennas performing fast measurements of the surrounding electric field. The antennas register high-velocity dust impacts through the electrical signatures of impact ionization. Although the basic principle of the detection has been known for decades, the understanding of the underlying process is not complete, due to the unique mechanical and electrical design of each spacecraft and the variability of the process. We present a study of electrical signatures of dust impacts on Solar Orbiter's body, as measured with the Radio and Plasma Waves electrical suite. A large proportion of the signatures present double-peak electrical waveforms in addition to the fast pre-spike due to electron motion, which are systematically observed for the first time. We believe this is due to Solar Orbiter's unique antenna design and a high temporal resolution of the measurements. The double peaks are explained as being due to two distinct processes. Qualitative and quantitative features of both peaks are described. The process for producing the primary peak has been studied extensively before, and the process for producing the secondary peak has been proposed before (Pantellini et al., 2012a) for Solar Terrestrial Relations Observatory (STEREO), although the corresponding delay of 100–300 µs between the primary and the secondary peak has not been observed until now. Based on this study, we conclude that the primary peak's amplitude is the better measure of the impact-produced charge, for which we find a typical value of around 8 pC. Therefore, the primary peak should be used to derive the impact-generated charge rather than the maximum. The observed asymmetry between the primary peaks measured with individual antennas is quantitatively explained as electrostatic induction. A relationship between the amplitude of the primary and the secondary peak is found to be non-linear, and the relation is partially explained with a model for electrical interaction through the antennas' photoelectron sheath.

Polar mesospheric summer echoes (PMSEs) are radar echoes that are measured in the upper atmosphere during the summer months and that can occur in several layers. In this study, we aimed to investigate the relationship between PMSE layers ranging from 80 to 90 km altitude and the solar cycle. We investigated 230 h of observations from the EISCAT very high frequency (VHF) radar located near Troms & oslash;, Norway, from the years 2013, 2014 and 2015 during the solar maximum and the years 2019 and 2020 during the solar minimum and applied a previously developed classification model to identify PMSE layers. Our analysis focused on parameters such as the altitude, thickness and echo power in the PMSE layers, as well as the number of layers present. Our results indicate that the average altitude of PMSEs, the echo power in the PMSEs and the thickness of the layers are, on average, higher during the solar maximum than during the solar minimum. In the considered observations, the electron density at 92 km altitude and the echo power in the PMSEs are positively correlated with the thickness of the layers except for four multilayers at solar minimum. We infer that higher electron densities at ionospheric altitudes might be necessary to observe multilayered PMSEs. We observe that the thickness decreases as the number of multilayers increases. We compare our results with previous studies and find that similar results regarding layer altitudes were found in earlier studies using observations with other VHF radars. We also observed that the bottom layer in the different sets of multilayers almost always aligned with the noctilucent cloud (NLC) altitude reported by previous studies at 83.3 km altitude. Also, an interesting parallel is seen between the thickness of NLC multilayers and PMSE multilayers, where both NLCs and PMSEs have a similar distribution of layers greater than 1 km in thickness. Future studies that include observations over longer periods would make it possible to distinguish the influence of the solar cycle from possible other long-term trends.

We investigate the collection of dust particles in the mesosphere with the MESS (MEteoric Smoke Sampler) instrument that is designed to fly on a sounding rocket. We assume that the ice particles that form in the polar mesosphere between 80 and 85 km altitude in summer contain meteoric smoke particles; and these should be collected with MESS. The instrument consists of a collection device with an opening and closure mechanism, as well as an attached conic funnel which increases the sampling area in comparison to the collection area. Dust particles are collected either directly after passing through the instrument or indirectly after colliding with and fragmenting on the funnel wall. We calculate the dust and fragment trajectories in the detector to determine the collection efficiency for different particle sizes, rocket velocities, and heights, and we find the final velocities and the temperatures of the particles. The considered design has a sampling area of 62.78 mm diameter and a collection area of 20 mm diameter. For the conditions at the rocket launch site in Andøya, Norway, we estimate the collection of meteoric smoke particles contained in the ice particles to be ∼ 1012–1014 amu mm−2. The estimated temperatures suggest that the composition of these smoke particles is not affected by the collection. Our calculations also show that keeping the instrument open above 85 km altitude increases the amount of small smoke particles that are directly collected. The directly collected smoke particles are heated as they decelerate, which can affect their composition.

Context. Parker Solar Probe (PSP) counts dust impacts in the near-solar region, but modeling effort is needed to understand the dust population's properties. Aims. We aim to constrain the dust cloud's properties based on the flux observed by PSP. Methods. We developed a forward model for the bound dust detection rates using the formalism of 6D phase space distribution of the dust. We applied the model to the location table of different PSP solar encounter groups. We explain some of the near-perihelion features observed in the data as well as the broader characteristic of the dust flux between 0.15 AU and 0.5 AU. We compare the measurements of PSP to the measurements of Solar Orbiter near 1 AU to expose the differences between the two spacecraft. Results. We found that the dust flux observed by PSP between 0.15 AU and 0.5 AU in post-perihelia can be explained by dust on bound orbits and is consistent with a broad range of orbital parameters, including dust on circular orbits. However, the dust number density as a function of the heliocentric distance and the scaling of detection efficiency with relative speed are important to explain the observed flux variation. The data suggest that the slope of differential mass distribution, delta, is between 0.14 and 0.49. The near-perihelion observations, however, show the flux maxima, which are inconsistent with the circular dust model, and additional effects may play a role. We found an indication that the sunward side of PSP is less sensitive to the dust impacts than PSP's other surfaces. Conclusions. We show that the dust flux on PSP can be explained by noncircular bound dust and the detection capabilities of PSP. The scaling of flux with impact speed is especially important, and shallower than previously assumed.

Meteoric ablation in the Earth's atmosphere produces particles of nanometer size and larger. These particles can become charged and influence the charge balance in the D region (60–90 km) and the incoherent scatter observed with radar from there. Radar studies have shown that, if enough dust particles are charged, they can influence the received radar spectrum below 100 km, provided the electron density is sufficiently high (>109 m3). Here, we study an observation made with the EISCAT VHF radar on 9 January 2014 during strong particle precipitation so that incoherent scatter was observed down to almost 60 km altitude. We found that the measured spectra were too narrow in comparison to the calculated spectra. Adjusting the collision frequency provided a better fit in the frequency range of ± 10–30 Hz. However, this did not lead to the best fit in all cases, especially not for the central part of the spectra in the narrow frequency range of ±10 Hz. By including a negatively charged dust component, we obtained a better fit for spectra observed at altitudes of 75–85 km, indicating that dust influences the incoherent-scatter spectrum at D-region altitudes. The observations at lower altitudes were limited by the small number of free electrons, and observations at higher altitudes were limited by the height resolution of the observations. Inferred dust number densities range from a few particles up to 104 cm−3, and average sizes range from approximately 0.6 to 1 nm. We find an acceptable agreement with the dust profiles calculated with the WACCM-CARMA (Whole Atmosphere Community Climate Model-Community Aerosol Radiation Model for Atmospheres) model. However, these do not include charging, which is also based on models.

We discuss a suite of instruments cable of carrying out the next generation of in situ cosmic dust measurements from the heliosphere into interstellar space in support of the Interstellar Probe mission concept.A Dust Analyzer should be considered as the highest priority for its coverage of both compositional and dynamical information of the bulk of interstellar dust (ISD) and interplanetary dust particle (IDP) populations, essential to address the major science questions.A PVDF Dust Counter and Plasma Wave Antenna instrument could additionally provide critical improvement through the detection of larger, rarer dust populations, to constraining the mass density of ISD as well as providing additional directionality coverage.A Neutral Mass Spectrometer bridges the measurement gap between microscopic dust grains and gas species, potentially relevant for understanding the nature and interactions of the very local interstellar medium and our heliosphere.The Dust Analyzer, PVDF Dust Counter, and Plasma Wave Antenna instruments can be calibrated using dust accelerator facilities (University of Colorado, USA, see Shu et al., 2012; and Universität Stuttgart, Germany) with ISD-relevant materials at realistic mass and speed ranges.

Polar mesospheric summer echo (PMSE) formation is linked to charged dust/ice particles in the mesosphere. We investigate the modulation of PMSEs with radio waves based on measurements with EISCAT VHF radar and EISCAT heating facility during low solar illumination. The measurements were made in August 2018 and 2020 around 20:02 UT. Heating was operated in cycles with intervals of 48 s on and 168 s off. More than half of the observed heating cycles show a PMSE modulation with a decrease in PMSE when the heater is on and an increase when it is switched off again. The PMSE often increases beyond its initial strength. Less than half of the observed modulations have such an overshoot. The overshoots are small or nonexistent at strong PMSE, and they are not observed when the ionosphere is influenced by particle precipitation. We observe instances of very large overshoots at weak PMSE. PMSE modulation varies strongly from one cycle to the next, being highly variable on spatial scales smaller than a kilometer and timescales shorter than the timescales assumed for the variation in dust parameters. Average curves over several heating cycles are similar to the overshoot curves predicted by theory and observed previously. Some of the individual curves show stronger overshoots than reported in previous studies, and they exceed the values predicted by theory. A possible explanation is that the dust-charging conditions are different either because of the reduced solar illumination around midnight or because of long-term changes in ice particles in the mesosphere. We conclude that it is not possible to reliably derive the dust-charging parameters from the observed PMSE modulations.

Synopsis.Interstellar dust (ISD) continuously flows through our solar system as we orbit within the Milky Way galaxy, carrying information about the upstream local interstellar material (ISM).As ISD grains encounter the heliosphere, they experience gravitational, solar radiation pressure, and electromagnetic forces, perturbing their trajectories in a time-, charge-, and size-dependent fashion, leading to complex variability in the ISD flux throughout the heliosphere.Despite having been detected within our heliosphere via insitu observations almost three decades ago, we still do not fully understand the nature of ISD, including its 'pristine' nature upstream of the heliosphere's influence or the details of its interaction with solar radiation and heliospheric electromagnetic fields.A deeper understanding of ISD grains and their interaction with the heliosphere offers an opportunity for insight into the conditions and forces driving the evolution of our global heliosphere and is thus deserving of sustained research in the next decade.In this white paper, we present compelling open scientific questions regarding interstellar dust and argue for multi-point measurements of ISD composition, flux, and variability throughout the heliosphere in the next decade.Introduction and Open Science Questions.As our Sun orbits around the Milky Way Galaxy, it encounters a wide variety of interstellar environments that interact with and ultimately dictate the size and shape of the heliosphere.In addition to interstellar magnetic fields, plasma, and neutral gas populations, interstellar dust has long been recognized as a critical component in heliospheric physics.

Incoherent scatter radars (ISRs) represent the only instrument (both ground and space based) capable of making high temporal and spatial resolution measurements of multiple atmospheric parameters—such as densities, temperatures, particle velocities, mass flux—over an altitude range covering the entire mesosphere/lower thermosphere/ionosphere (MLTI) system on a quasi-continuous basis. The EISCAT Svalbard incoherent scatter radar (ESR), located just outside Longyearbyen (78.15 ^∘ N) on Svalbard, is the only currently operating facility capable of making such measurements inside the polar cusp—an area of significant energy input into the atmosphere and characterized by heating instabilities and turbulence. The ESR was built in the mid-1990s and has provided valuable data for the international experimental and modelling communities. New radar technologies are now available, in the form of phased array systems, which offer new data products and operational flexibility. This paper outlines the achievements and current research focus of the ESR and provides scientific arguments, compiled from inputs across the international scientific community, for a new phased array ISR facility on Svalbard. In addition to the fundamental scientific arguments, the paper discusses additional benefits of continued ISR observations on Svalbard, building on the key findings of the ESR. Svalbard has a large network of complementary instrumentation both focused on the MLTI system (e.g. the Kjell Henriksen auroral Observatory, the Svalbard SuperDARN radar and the Svalrak sounding rocket launch facility) with synergies to other research fields, such as meteorology and oceanography. As a further holistic system science view of the Earth becomes more important, a new ISR on Svalbard will be important also in this respect with its ability to provide datasets with a wide range of scientific applications. Increased activity in space has highlighted problematic issues such as space debris. A changing Arctic has also seen increased human activity via the opening up of new shipping routes, which are reliant on GNSS technology that is effected by severe turbulence in the MLTI system. As such, societal applications of a future ISR are also presented. The accessibility and logistical support for such a facility is also briefly discussed.

&lt;p&gt;Atmospheric Gravity Waves (AGWs) forced in the lower atmosphere are known to have a significant impact on the mesosphere and lower thermosphere (MLT) region. In the ionosphere, they can generate Medium-Scale Traveling Ionospheric Disturbances (MSTIDs). These disturbances roughly occur on time scales of 15&amp;#8722;80 min and are therefore often parametrized rather than directly resolved in ionosphere models. The energy and momentum transport by AGW-TIDs strongly depends on their wave parameters. Measurements of AGW-TIDs in the MLT region and determination of the wave parameters (vertical and horizontal wavelength, wave period and propagation direction) are therefore an essential step to improve ionosphere modelling. However, measurements that provide a good resolution in the vertical dimension (&amp;#8818; 10 km) and time (&amp;#8818; 10 min) as well as a large enough coverage in the horizontal dimension (&amp;#8819; 300 &amp;#215; 300 km) are difficult at MLT altitudes. We show, that combined measurements of the EISCAT VHF incoherent scatter radar and the Nordic Meteor Radar Cluster allow to determine the wave parameters of AGW-TIDs across the whole MLT region. Fourier filter methods are used to separate wave modes by wavelength, period and propagation direction. The extracted wave modes are fitted with wave functions in time-altitude and horizontal cross sections which gives the wave parameters. The coverage regions of the two applied instruments are separated only by approximately 10 km in altitude, which allows to identify a single wave mode in both measurements. We present the developed techniques on the example of a strongly pronounced AGW-TID measured on July 7, 2020. As a first application, two measurement campaigns have been conducted in early September and mid-October 2022 to study possible changes in AGW-TID parameters due to the MLT fall transition occurring around equinox. Another possible application of our method is to infer thermospheric neutral winds from the observed waves. We demonstrate this process under the assumption of the anelastic dissipative gravity wave dispersion relation.&lt;/p&gt;

Dusty plasmas are electrically quasi-neutral media that, along with electrons, ions, neutral gas, radiation, and electric and/or magnetic fields, also contain solid or liquid particles with sizes ranging from a few nanometers to a few micrometers. These media can be found in many natural environments as well as in various laboratory setups and industrial applications. As a separate branch of plasma physics, the field of dusty plasma physics was born in the beginning of 1990s at the intersection of the interests of the communities investigating astrophysical and technological plasmas. An additional boost to the development of the field was given by the discovery of plasma crystals leading to a series of microgravity experiments of which the purpose was to investigate generic phenomena in condensed matter physics using strongly coupled complex (dusty) plasmas as model systems. Finally, the field has gained an increasing amount of attention due to its inevitable connection to the development of novel applications ranging from the synthesis of functional nanoparticles to nuclear fusion and from particle sensing and diagnostics to nano-contamination control. The purpose of the present perspectives paper is to identify promising new developments and research directions for the field. As such, dusty plasmas are considered in their entire variety: from classical low-pressure noble-gas dusty discharges to atmospheric pressure plasmas with aerosols and from rarefied astrophysical plasmas to dense plasmas in nuclear fusion devices. Both fundamental and application aspects are covered.

Context.Solar Orbiter provides dust detection capability in the inner heliosphere, but estimating physical properties of detected dust from the collected data is far from straightforward.Aims.First, a physical model for dust collection considering a Poisson process is formulated. Second, it is shown that dust on hyperbolic orbits is responsible for the majority of dust detections with Solar Orbiter’s Radio and Plasma Waves (RPW). Third, the model for dust counts is fitted to Solar Orbiter RPW data and parameters of the dust are inferred, namely radial velocity, hyperbolic meteoroids predominance, and the solar radiation pressure to gravity ratio as well as the uncertainties of these.Methods.Nonparametric model fitting was used to get the difference between the inbound and outbound detection rate and dust radial velocity was thus estimated. A hierarchical Bayesian model was formulated and applied to available Solar Orbiter RPW data. The model uses the methodology of integrated nested Laplace approximation, estimating parameters of dust and their ncertainties.Results.Solar Orbiter RPW dust observations can be modeled as a Poisson process in a Bayesian framework and observations up to this date are consistent with the hyperbolic dust model with an additional background component. Analysis suggests a radial velocity of the hyperbolic component around (63 ± 7) km s−1with the predominance of hyperbolic dust being about (78 ± 4)%. The results are consistent with hyperbolic meteoroids originating between 0.02 AU and 0.1 AU and showing substantial deceleration, which implies effective solar radiation pressure to a gravity ratio ≳ 0.5. The flux of the hyperbolic component at 1 AU is found to be (1.1 ± 0.2) × 10−4m−2s−1and the flux of the background component at 1 AU is found to be (5.4 ± 1.5) × 10−5m−2s−1.