Particles In Interplanetary Space Research Articles

Analysis of Ulysses data: Radiation pressure effects on dust particles

The objective of this paper is to illustrate the influence of the radiation pressure and the electromagnetic force on dust particles in interplanetary space. Between 1990 and 2001 62 so-called β-meteoroids (β describes the ratio of the radiation pressure force to gravity) were detected as dust particles coming from the inner solar system on hyperbolic orbits. 24 of them were detected shortly after the launch of Ulysses within the ecliptic and 38 of them were recorded primarily passing the Solar poles. Furthermore high speed particles not coming from the direction of the Sun were ejected from the solar system by electromagnetic forces. For the time period until the end of 2008 the effective area for particles coming from the direction of the Sun has been determined. The particles' perihelion distances indicated that they originated within a region of 0.5 AU from the Sun. For the second orbit of Ulysses the flux of β-meteoroids was determined using the same method as during its first revolution. Because of the more defocusing phase during the first orbit of Ulysses the production rate of β-meteoroids has been estimated to be nearly twice of that for the second revolution. On the other hand, an imbalance of the identified β-meteoroids between the north and south pole could not be explained by the solar cycle.

Spurious forces on the LISA proof masses due to electrostatic charging

Electrostatic charging of the LISA proof masses by penetrating cosmic rays and energetic solar particles in interplanetary space leads to two kinds of spurious forces: i) Lorentz interaction due to the motion of the charged proof masses through the interplanetary magnetic field, and ii) Coulomb interaction between the charged proof masses and surrounding conducting surfaces. Estimates of charging rates have been computed using the GEANT Monte Carlo particle-transport code in combination with realistic proton flux models.

Noble gases in interplanetary dust particles, I: The excess helium‐3 problem and estimates of the relative fluxes of solar wind and solar energetic particles in interplanetary space

Abstract— We report mass‐spectrometric measurements of light noble gases pyrolytically extracted from 28 interplanetary dust particles (IDPs) and discuss these new data in the context of earlier analyses of 44 IDPs at the University of Minnesota. The noble gas database for IDPs is still very sparse, especially given their wide mineralogic and chemical variability, but two intriguing differences from isotopic distributions observed in lunar and meteoritic regolith grains are already apparent. First are puzzling overabundances of 3He, manifested as often strikingly elevated 3He/4He ratios—up to >40x the solar‐wind value—‐and found primarily but not exclusively in shards of some of the larger IDPs (“cluster particles”) that fragmented on impact with the collectors carried by high‐altitude aircraft. It is difficult to attribute these high ratios to 3He production by cosmic‐ray‐induced spallation during estimated space residence times of IDPs, or by direct implantation of solar‐flare He. Minimum exposure ages inferred from the 3He excesses range from ∼50 Ma to an impossible >10 Ga, compared to Poynting‐Robertson drag lifetimes for low‐density 20–30 μm particles on the order of ∼0.1 Ma for an asteroidal source and ∼10 Ma for origin in the Kuiper belt. The second difference is a dominant contribution of solar‐energetic‐particle (SEP) gases, to the virtual exclusion of solar‐wind (SW) components, in several particles scattered throughout the various datasets but most clearly and consistently observed in recent measurements of a group of individual and cluster IDPs from three different collectors. Values of the SEP/SW fluence ratio in interplanetary space from a simple model utilizing these data are ∼1% of the relative SEP/SW abundances observed in lunar regolith grains, but still factors of approximately 10–100 above estimates for this ratio in low‐energy solar particle emission.

Low‐energy (<1.6 MeV) particle counting rates and solar magnetic activity: A study of the 1980 anomaly

We present a study of the relation between the solar magnetic activity (centered in sunspots, flares types N and B, and long‐duration X class flares) and the counting rates of particles in interplanetary space with energies below 1.6 MeV obtained from the Low‐Energy Proton Experiment (DFH‐EPAS) onboard International Sun‐Earth Explorer spacecraft, during the period 1978–1982. Our study shows that the particle counting rates are neither correlated with sunspots number nor with flares type N, but they are correlated with flares type B and mainly with long‐duration X class flares. The origin of the low counting rates of particles detected during the years 1979–1980 is investigated as well. The disappearance of the strongest interplanetary shocks during that period can explain this phenomenon, at least within the energy range studied. The absence of any anomalous behavior in the flares type B and in the long‐duration X class flares during this period suggests that this shock behavior can be produced by anomalous conditions of the interplanetary magnetic field during the Sun's polar magnetic field reversal.

A Reformulation of Divine's Interplanetary Model

Divine (1993) developed a mathematical model to use measurements of interplanetary dust to determine the orbital distributions of particles in interplanetary space. The power of the model is that it uses the fact that the dust particles are in Keplerian orbits to correct for the observation biases based on spatial density and velocity efifects of the orbits. In order to do this, he creates families of dust orbits; within each of which the particles have mathematically separable distributions of mass, periapsis, eccentricity, and inclination. He then uses a trial-and-error method to vary these distributions until an adequate fit is made to the data. Each of his distributions is loosely based on populations of interplanetary dust that are believed to be present in the Solar System.

Focused transport of energetic particles along magnetic field lines draped around a coronal mass ejection

The transport of particles in interplanetary space can be dominated by adiabatic focusing of particle pitch angle distributions under conditions when the ratio of the particle scattering mean free path to the magnetic field focusing length, λ/L, is ∼1. Since for the average Archimedean spiral field configuration, L ∼ 1 AU at Earth orbit, the only reported events dominated by focusing are those nearly “scatter‐free” events where λ ∼ 1 AU. However, if the interplanetary magnetic field is distorted so that the focusing length L is small, then even if the interplanetary scattering mean free path were small, focused transport would be expected to dominate, since λ/L would still be ∼1. We present evidence for such a event, obtained with observations of ∼0.1–1 MeV nucleon−1 protons and alpha particles obtained with the University of Maryland/Max‐Planck‐Institut experiment on the ISEE 3 spacecraft during the decay phase of the June 6, 1979, solar particle event. During the early portion of the decay phase of this event, interplanetary magnetic field lines were apparently draped around a coronal mass ejection, leading to a small focusing length L on the western flank where ISEE 3 was located. We observed a period of very slow decrease of particle intensity, along with large sunward anisotropy in the solar wind frame, which are inconsistent with predictions of the standard Fokker‐Planck equation models for diffusive transport; however, we are able to fit the observations assuming that focused transport dominates and that the particle pitch angle scattering is isotropic.

Interplanetary dust particles collected in the stratosphere: Observations of atmospheric heating and constraints on their interrelationship and sources

The majority of the interplanetary dust particles (IDPs) collected in the stratosphere belong to one of three major classes, the first two dominated by the anhydrous minerals olivine and pyroxene, and the third by hydrous layer-lattice silicates. Infrared spectroscopy and transmission electron microscopy studies show that the different IDP classes represent different types of dust that exist as individual particles in interplanetary space. The majority of the collected IDPs smaller than 30 μm in diameter in the layer-lattice silicate and pyroxene classes appear not to have been heated to temperatures above 600°C during atmospheric entry. The relatively low maximum temperatures experienced by these IDPs during atmospheric entry imply that they arrive at the top of the atmosphere with low geocentric encounter velocities. This limits the possible encounter trajectories for these particles to relatively circular, prograde orbits. As a result, it is unlikely that these IDPs are from Earth-crossing comets or asteroids. Asteroids, and comets having low inclinations and perihelia outside 1.2 UA, appear to be the best candidates for the parent bodies of the pyroxene and layer-lattice silicate particles. Chemical and mineralogical information suggests that the pyroxene-rich IDPs are from comets and layer-lattice silicate-rich IDPs are from asteroids. The collected IDPs dominated by olivine appear to include a larger fraction of particles heating above 600°C, suggesting that these particles were captured from more eccentric orbits. This, and the observation of the infrared spectral features of olivine in several comets suggest these particles have a cometary origin. Since much of the collected dust has apparently been captured from nearly circular, prograde orbits and since there are no appropriate parent bodies presently in such orbits, these results provide an experimental confirmation that the Poynting-Robertson effect exists as a nongravitational force important in the orbital evolution of dust in the Solar System.

Studies of low-energy HZE cosmic rays on cosmos satellites

Fluxes of ions with energies below 20 MeV/nucleon have been studied in a series of experiments performed in near-Earth space at an altitude of about 300 km. Use was made of polymeric dielectric track detectors. It was found that, after the solar maximum of 1981–1982, fluxes of ions of the anomalous oxygen component first appeared in near-Earth space in 1984 and reached their maximum in 1987. The values for the oxygen ion fluxes recorded in quasi-circular satellite orbits are in agreement with the data for fluxes of the same particles in interplanetary space, given the assumption that the oxygen ions are singly charged.

The US Max '91 program of flare research at the next solar maximum

The proposed US program of flare research at the next solar maximum, called Max '91, is described in a booklet available from the author. The scientific objective of Max '91 is to investigate the fundamental unsolved problems of flare physics including the processes of energy storage, release, and transport, and particle acceleration. To address these central scientific issues, the Max '91 observing program will utilize advanced instrumentation on spacecraft, rockets, and balloons, and at ground-based observatories. It will cover the electromagnetic spectrum from radio through optical to X-rays and gamma-rays, and will include measurements of neutrons and charged particles in interplanetary space. Max '91 is designed to make major advances in solar flare physics through observations of high energy flare phenomena and of the magnetic and thermal context in which they take place. This will be achieved using recent advances in instrumentation technology that now make it possible, for the first time, to observe several of the most important processes on their intrinsic spatial, spectral and temporal scales.

ISEE 3 observations of low‐energy proton bidirectional events and their relation to isolated interplanetary magnetic structures

Bidirectional, field‐aligned flows of low‐energy particles in interplanetary space have been proposed as a possible signature of large‐scale, looplike magnetic structures. We present the results of a survey of bidirectional anisotropy observations using data from the low‐energy proton and magnetometer experiments on board ISEE 3 covering a 45‐month period corresponding to the last solar maximum. During this period, 66 bidirectional flow (BDF) events have been identified, of which 48 could positively be associated with isolated magnetic field structures. We suggest that these structures are an interplanetary manifestation of coronal mass ejection (CME) events, and are able to group the BDF events into five classes according to the field signature of the related magnetic structure and the association or otherwise with an interplanetary shock. We conclude that the BDF events are an interplanetary signature not only of energetic, flare‐associated transients but also low energy, nonflare CMEs. From a comparison of anisotropy signatures at 35 and 620 keV we conclude that our observations are most consistent with the transient magnetic structures being detached bubbles comprising closed loops or tightly wound cylindrical helices rather than extended tonguelike loops attached to the Sun at the time of observation.

Drift motion and perpendicular diffusion of energetic particles in interplanetary space based on spacecraft data

A realistic model of the interplanetary magnetic field (IMF) is constructed based on measurements taken by Pioneer 10 magnetometer at 5 AU. Energetic particle (0.1–100 MeV) propagation in this field is studied by a computer simulation of its motion in order to calculateK⊥, the perpendicular diffusion coefficient, and 〈V D 〉 the average drift velocity of an ensemble of particles. Determinations ofK⊥ lie in the range 3×1019–8×1020 cm2 s−1 for the energies considered and they show that perpendicular diffusion may be an important process at these heliodistances when compared with parallel diffusion results obtained by similar techniques, contrary to what was previously thought. Drift velocity calculations are very close to predictions of guiding centre theory (within 30%) suggesting that this theory can be applied in the IMF. This result shows that gradient and curvature drifts can be present even in a highly perturbed field and thus they can have some influence in cosmic ray modulation.

The chemical composition of energetic charged particles in interplanetary space

The particle population in the heliosphere is briefly reviewed. Next the chemical composition of the charged fraction is reviewed by discussing three classes. The galactic cosmic rays and high energy solar flare particles above 100 MeV/nucleon are mentioned. The anomalous component in the range 1-100 MeV/nucleon, prompt solar flare particles, energetic storm particles and corotating events are discussed. The anomalous variations in isotopic ( 3 He) and chemical composition (iron-rich events) at energies below 10 MeV are reviewed. A discussion on the ionic charge state of these particles concludes this overview.

The Motion of Charged Dust Particles in Interplanetary Space

The problem of electromagnetic perturbations of charged dust particle orbits in interplanetary space has been re-examined in the light of our better understanding of the large scale spatial and temporal interplanetary plasma and field topology. In the equatorial plane, the magnetic sectors, caused by the warped current sheet, produce stochastic orbit perturbations. From this a diffusive description of particle motion can be derived, provided the dust particles are sufficiently small. The effects of large unipolar magnetic field regions at high heliographic latitudes will be briefly discussed.

The motion of charged dust particles in interplanetary space—II. Interstellar grains

The effects of electromagnetic forces on charged interstellar grains entering the heliosphere are re-examined. It is shown that the unipolar field regimes at high latitudes lead either to a “focusing” or a “defocusing” of interstellar dust particles with respect to the solar magnetic equator, and that the stochastic magnetic fluctuations in the equatorial region, caused by the warping of the current sheet which separates the polar fields, lead to a diffusive description of particle transport at the low mass end. Consequences for the ability of interstellar dust particles to penetrate the inner heliosphere are discussed. It is concluded that dust particles with radii s > 10 −5 cm can penetrate deeply into the heliosphere if their incidence direction at the heliopause is almost radially inward and close to the solar magnetic equatorial plane, whereas dust particles with radii s < 10 −5 cm are prevented from reaching the inner heliosphere. This implies that in situ detectors should only be able to observe “core-mantle” particles in the inner heliosphere, but not interstellar “cores”. Even this observation should only be possible during favourable solar cycles, when the particles are focused towards the solar magnetic equator.

The motion of charged dust particles in interplanetary space—I. The zodiacal dust cloud

The problem of electromagnetic perturbations of charged dust particle orbits in interplanetary space has been re-examined in the light of our better understanding of the large scale spatial and temporal interplanetary plasma and field topology. Using both analytical and numerical solutions for particle propagation it was shown that: (1) stochastic variations induced by electromagnetic forces are unimportant for the zodiacal dust cloud except for the lowest masses, (2) systemetic variations in orbit inclinations are unimportant if orbital radii are larger than 10 a.u. This is due to the solar cycle variation in magnetic polarity which tends to cancel out systematic effects, (3) systematic variations in orbital parameters (inclination, longitude of ascending node, longitude of perihel) induced by electromagnetic forces inside 1 a.u. tend to shift the plane of symmetry of the zodiacal dust cloud somewhat towards the solar magnetic equatorial plane, (4) inside 0.3 a.u. there is a possibility that dust particles may enter a region of “magnetically resonant” orbits for some time. Changes in orbit parameters are then correspondingly enhanced, (5) the observed similarity of the plane of symmetry of zodiacal light with the solar equatorial plane may be the effect of the interaction of charged interplanetary dust particles with the interplanetary magnetic field. Numerical orbit calculation of dust particles show that one of the results of this interaction is the rotation of the orbit plane about the solar rotational axis.

Entry of solar protons to the plasma sheet and lobe of the magnetotail at r=18 RE in the event of April 22, 1971

Vela satellites of orbit r=18 RE measured the intensity of ≲1‐MeV solar protons at two points in the plasma sheet and one in the north tail lobe during an 8‐hour period on April 22, 1971. Intensities were isotropic, except when a sharp gradient was convected past a satellite. Several such gradients have been interpreted as the boundary between plasma sheet and north lobe. Movement of this plasma sheet surface has been observed in coincidence with substorm and geomagnetic storm activity. It is inferred that the region of open field lines at Vela orbit was very small in this event. A prolonged intensity difference by a factor of almost 2 existed across the surface between plasma sheet and lobe for &gt;8 hours, implying very little cross‐field transport of ≲1‐MeV protons. One gradient‐induced anisotropy was anomalous in direction and has been explained by a tongue‐shaped distortion in the surface separating plasma sheet and lobe. A second case of anomalous anisotropy from another event has been explained in a similar way. Intercomparison between Vela and Imp 6, the latter in interplanetary space, suggests the following. Access of ≲1‐MeV solar protons to the north tail lobe was delayed by 3–4 hours, giving an access point 602–872 RE from earth. The intensity there was a little higher than the mean of the interplanetary distribution. The intensity in the dusk plasma sheet lay between the mean in interplanetary space and the integrated intensity of the backward moving interplanetary particles (−1 &lt; µ &lt; 0). The intensity in the dawn plasma sheet was lower and tracked the integrated intensity of the backward moving particles in interplanetary space. This gradient across the plasma sheet at r=18 RE implies that there was not a thorough mixing of ≲1‐MeV protons, at least on a time scale of hours.

Mariner-Jupiter-Saturn Low Energy Charged Particle Experiment

The Low Energy Charged Particle Experiment shown in Figure 1 will be launched on the Mariner-Jupiter-Saturn spacecraft in August 1977. The experiment has been designed to perform particle measurements in the intense radiation belts of the Jovian and Saturnian environments, and to provide detailed spectral analysis of both solar and galactic particles in interplanetary space. These objectives are met by a single instrument which uses 23 solid-state detectors configured in two distinct detector subsystems. One subsystem is optimized for interplanetary and interstellar measurements. The second subsystem is optimized for specific particle species, energies, and intensities expected near the planets. Angular distributions in the ecliptic plane and pitch angle distributions are obtained using an 8-sector scanning motor.

5.6 Radial Distribution of Meteoric Particles in Interplanetary Space

An attempt has been made to derive heliocentric distribution of meteoric particles in interplanetary space. Poynting-Robertson effect, collision process, and cometary dust injection have been included in this study. Three different radial distribution functions for different sizes have been derived. The number density appears to depend on particle size.

5.3 Modeling of the Orbital Evolution of Vaporizing Dust Particles Near the Sun

AbstractThe Poynting-Robertson (P-R) effect (Robertson, 1937, Wyatt and Whipple, 1950), assisted by a pseudo P-R effect due to the sputtering (Whipple, 1955, 1967), is known to cause small dust particles in interplanetary space to spiral toward the sun. Evaporation from the surface of such particles thus increases progressively with time and their size is being reduced accordingly. When the rate of evaporation is no longer negligibly low, it induces on the particle a measurable dynamical effect, which is associated with the implied variations in the magnitude of solar radiation pressure relative to solar attraction. By gradually reducing solar attraction, the particle evaporation tends to increase the orbit dimensions, thus acting against P-R. The P-R inward spiraling, far exceeding the dynamical effect from evaporation at larger heliocentric distances, slows gradually down as the particle approaches the sun, and virtually ceases when the critical distance is reached, where the two forces approximately balance each other. Then, typically, the perihelion distance stabilizes, while the eccentricity starts increasing very rapidly until the particle is swept out of the solar system. This, in brief, is the orbital evolution of a vaporizing particle in the absence of other potentially important but rather poorly known processes, such as particle collisions, rotational bursting, electric charging and interactions with the solar wind and with the interplanetary magnetic field.

Apollo 17 cosmic-ray experiment - Interplanetary heavy nuclei of energies 0.05 to 5.0 MeV per atomic mass unit

view Abstract Citations (1) References (31) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Apollo 17 cosmic-ray experiment: interplanetary heavy nuclei of energies 0.05 to 5.0 MeV per atomic mass unit. Woods, R. T. ; Hart, H. R., Jr. ; Fleischer, R. L. Abstract Glass detectors were exposed to interplanetary heavy ions for 45.5 hr on the moon during Dec. 12 and 13, 1972. In the energy range 0.05-5.0 MeV per amu, the differential flux of iron-group nuclei was found to be a power-law spectrum of the form 1/E cubed. During the experiment, solar activity was low, as inferred from both ground-based observations of solar activity and satellite measurements of particles in interplanetary space. The Fe/alpha-ratio at about 1 MeV per amu was enhanced by a factor of about 10 above the solar ratio. A pair of detectors that were exposed in both the solar and antisolar directions gave identical spectral shapes, with the flux from the solar direction being twice that from the antisolar direction. Collectively, the observations of solar-related anisotropy and the 1/E cubed spectra, and the factor of about 10 enhancement in the Fe/alpha-ratio, imply strongly that these heavy ions are solar in origin. Publication: The Astrophysical Journal Pub Date: May 1975 DOI: 10.1086/153591 Bibcode: 1975ApJ...198..183W Keywords: Apollo 17 Flight; Cosmic Rays; Heavy Nuclei; Interplanetary Space; Solar Activity Effects; Corpuscular Radiation; Heavy Ions; Power Spectra; Spaceborne Astronomy; Space Radiation full text sources ADS |