Solar wind He pickup ions as source of tens-of-keV/n neutral He atoms observed by the HSTOF/SOHO detector

Grzędzielski, S.; Swaczyna, P.; Czechowski, A.; Hilchenbach, M.

doi:10.1051/0004-6361/201322927

Cited by 6 publications

(17 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Due to various possible implementations of ENA detectors in future space experiments, the estimations are performed for all sky observations for a wide range of energies from 0.2 keV/nuc to 130 keV/nuc, or equivalently for speeds from 200 km s −1 to 5000 km s −1 . The method used in this paper follows the scheme presented in Grzedzielski et al (2013Grzedzielski et al ( , 2014, and in Paper I, with some modifications discussed below. The modifications are employed to allow for the analysis of heavier elements with a limited knowledge of the reaction cross-sections.…”

Section: Methodsmentioning

confidence: 99%

“…However, the modeled signal was significantly larger than the observed one. Grzedzielski et al (2014) extended the model to the higher energies and were able to match the HSTOF observations using Voyagers observations of the PUIs spectrum in the inner heliosheath (Stone et al 2008), as well as the thickness of the inner heliosheath obtained from in situ observations Stone et al 2013). …”

Section: Introductionmentioning

confidence: 98%

See 1 more Smart Citation

Modeling Emission of Heavy Energetic Neutral Atoms from the Heliosphere

Swaczyna

Bzowski

2017

ApJ

View full text Add to dashboard Cite

Observations of energetic neutral atoms (ENAs) are a fruitful tool for remote diagnosis of the plasma in the heliosphere and its vicinity. So far, instruments detecting ENAs from the heliosphere were configured for observations of hydrogen atoms. Here, we estimate emissions of ENAs of the heavy chemical elements helium, oxygen, nitrogen, and neon. A large portion of the heliospheric ENAs is created in the inner heliosheath from neutralized interstellar pick-up ions (PUIs). We modeled this process and calculated full-sky intensities of ENAs for energies 0.2-130 keV/nuc. We found that the largest fluxes among considered species are expected for helium, smaller for oxygen and nitrogen, and smallest for neon. The obtained intensities are 50-10 6 times smaller than the hydrogen ENA intensities observed by IBEX. The detection of heavy ENAs will be possible if a future ENA detector is equipped with the capability to measure the masses of observed atoms. Because of different reaction cross-sections among the different species, observations of heavy ENAs can allow for a better understanding of global structure of the heliosphere as well as the transport and energization of PUIs in the heliosphere.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Modeling Emission of Heavy Energetic Neutral Atoms from the Heliosphere

Swaczyna

Bzowski

2017

ApJ

View full text Add to dashboard Cite

show abstract

“…Here, the method used previously by Grzedzielski et al (2010bGrzedzielski et al ( , 2013Grzedzielski et al ( , 2014 is developed for an extended energy range from 0.1 keV/nuc up to 1 MeV/nuc.…”

Section: He Ena From the Inner Heliosheathmentioning

confidence: 99%

“…This potential was used by Grzedzielski et al (2014). The above-mentioned potentials assume a purely hydrodynamical flow and do not include deceleration of the heliosheath plasma due to charge exchanges of plasma ions with the interstellar neutral atoms.…”

Section: Model Of the Plasma Flow In The Inner Heliosheathmentioning

confidence: 99%

“…The obtained values of n i are in a relatively good agreement with the Voyager 1 observations of 0.08 cm −3 from the Note-Parameters for the flow potential given by Equation (4) with Φ0 = ΦSN. ΦG2014 present parameters used in Grzedzielski et al (2014) observed plasma oscillations (Gurnett et al 2013). A summary of the adopted values of the flow potential parameters is presented in Table 1.…”

Section: Model Of the Plasma Flow In The Inner Heliosheathmentioning

confidence: 99%

See 1 more Smart Citation

Helium Energetic Neutral Atoms from the Heliosphere: Perspectives for Future Observations

Swaczyna

Grzędzielski

Bzowski

2017

ApJ

View full text Add to dashboard Cite

Observations of energetic neutral atoms (ENAs) allow for remote sensing of plasma properties in distant regions of the heliosphere. So far, most of the observations have concerned only hydrogen atoms. In this paper, we present perspectives for observations of helium energetic neutral atoms (He ENAs). We calculated the expected intensities of He ENAs created by the neutralization of helium ions in the inner heliosheath and through the secondary ENA mechanism in the outer heliosheath. We found that the dominant source region for He ENAs is the inner heliosheath. The obtained magnitudes of intensity spectra suggest that He ENAs can be observed with future ENA detectors, as those planned on Interstellar Mapping and Acceleration Probe. Observing He ENAs is most likely for energies from a few to a few tens of keV/nuc. Estimates of the expected count rates show that the ratio of helium to hydrogen atoms registered in the detectors can be as low as 1:10 4 . Consequently, the detectors need to be equipped with an appropriate mass spectrometer capability, allowing for recognition of chemical elements. Due to the long mean free paths of helium ions in the inner heliosheath, He ENAs are produced also in the distant heliospheric tail. This implies that observations of He ENAs can resolve its structure, which seems challenging from observations of hydrogen ENAs since energetic protons are neutralized before they progress deeper in the heliospheric tail.

show abstract

Reconstruction of Helio-Latitudinal Structure of the Solar Wind Proton Speed and Density

et al. 2015

View full text Add to dashboard Cite

The modeling of the heliosphere requires continuous three-dimensional solar wind data. The in-situ out-of-ecliptic measurements are very rare, so that other methods of solar wind detection are needed. We use the remote-sensing data of the solar wind speed from observations of interplanetary scintillation (IPS) to reconstruct spatial and temporal structures of the solar wind proton speed from 1985 to 2013. We developed a method of filling the data gaps in the IPS observations to obtain continuous and homogeneous solar wind speed records. We also present a method to retrieve the solar wind density from the solar wind speed, utilizing the invariance of the solar wind dynamic pressure and energy flux with latitude. To construct the synoptic maps of the solar wind speed we use the decomposition into spherical harmonics of each of the Carrington rotation map. To fill the gaps in time we apply the singular spectrum analysis to the time series of the coefficients of spherical harmonics. We obtained helio-latitudinal profiles of the solar wind proton speed and density over almost three recent solar cycles. The accuracy in the reconstruction is, due to computational limitations, about 20 %. The proposed methods allow us to improve the spatial and temporal resolution of the model of the solar wind parameters presented in our previous paper (Sokół et al., Solar Phys. 285, 167, 2013) and give a better insight into the time variations of the solar wind structure. Additionally, the solar wind density is reconstructed more accurately and it fits better to the in-situ measurements from Ulysses.

show abstract

Solar wind He pickup ions as source of tens-of-keV/n neutral He atoms observed by the HSTOF/SOHO detector

Cited by 6 publications

References 30 publications

Modeling Emission of Heavy Energetic Neutral Atoms from the Heliosphere

Modeling Emission of Heavy Energetic Neutral Atoms from the Heliosphere

Helium Energetic Neutral Atoms from the Heliosphere: Perspectives for Future Observations

Reconstruction of Helio-Latitudinal Structure of the Solar Wind Proton Speed and Density

Contact Info

Product

Resources

About