Charge transfer cross sections for energetic neutral atom data analysis

Lindsay, B. G.; Stebbings, R. F.

doi:10.1029/2005ja011298

Cited by 301 publications

(312 citation statements)

References 79 publications

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“…The charge exchange reaction was recently discussed by Bzowski et al (2013) for heliospheric H and most of the theory applies for O, Ne, and He. The charge exchange cross sections for He and O used in the present paper come from Lindsay & Stebbings (2005) and for Ne from Nakai et al (1987). Figure A.7 shows the product of the relative speed of the component of the reaction and cross section for charge exchange for the NIS species observed by IBEX.…”

Section: A2 Electron Impact Ionization Of Ne He and Omentioning

confidence: 99%

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Modulation of neutral interstellar He, Ne, O in the heliosphere. Survival probabilities and abundances at IBEX

Bzowski

Sokół

Kubiak

et al. 2013

A&A

111

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Context. Direct sampling of neutral interstellar (NIS) atoms by the Interstellar Boundary Explorer (IBEX) can potentially provide a complementary method for studying element abundances in the Local Interstellar Cloud (LIC) and processes in the heliosphere interface. Aims. We set the stage for abundance-aimed in-depth analysis of measurements of NIS He, Ne, and O by IBEX and determine systematic differences between abundances derived from various calculation methods and their uncertainties.Methods. Using a model of ionization rates of the NIS species in the heliosphere, based on independent measurements of the solar wind and solar EUV radiation, we developed a time-dependent method of calculating the survival probabilities of NIS atoms from the termination shock (TS) of the solar wind to IBEX. With them, we calculated densities of these species along the Earth's orbit and simulated the fluxes of NIS species as observed by IBEX. We studied pairwise ratios of survival probabilities, densities, and fluxes of NIS species at IBEX to calculate correction factors for inferring the abundances at TS. Results. The analytic method of calculating the survival probabilities gives acceptable results only for He and Ne during low solar activity. For the remaining portions of the solar cycle, and at all times for O, a fully time-dependent model should be used. Electronimpact ionization is surprisingly important for NIS O. Interpreting the IBEX observations using the time-dependent model yields the LIC Ne/O abundance of 0.16 ± 40%. The uncertainty is mostly due to uncertainties in the ionization rates and in the NIS gas flow vector. Conclusions. The Ne/He, O/He, and Ne/O ratios for survival probabilities, local densities, and fluxes scaled to TS systematically differ and thus an analysis based only on survival probabilities or densities is not recommended, except the Ne/O abundance for observations at low solar activity.

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Section: A2 Electron Impact Ionization Of Ne He and Omentioning

confidence: 99%

“…Other ions in the solar wind are not abundant enough to have a nonnegligible effect (Zurbuchen et al 2002). The cross section for this reaction was taken from Lindsay & Stebbings (2005), who conservatively assess its accuracy in the energy range relevant for our applications at 25%.…”

Section: Charge Exchangementioning

confidence: 99%

Modulation of neutral interstellar He, Ne, O in the heliosphere. Survival probabilities and abundances at IBEX

Bzowski

Sokół

Kubiak

et al. 2013

A&A

111

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“…Charge-exchange cross sections were calculated using the fits from Barnett et al (1990). For the H+H + charge exchange cross section the difference between Barnett et al and the more recent fit (Lindsay & Stebbings 2005) is of the order of few percent except for the energy region between ∼10 and ∼70 keV where the Lindsay & Stebbings cross section is larger by up to 30% (at 30 keV) and by 15−20% in the HSTOF energy range. The ordering of terms in Eq.…”

Section: Particle Distributions In the Heliosheathmentioning

confidence: 99%

HSTOF ENA observations and energetic ion distributions in the heliosheath

Czechowski

Hilchenbach

Hsieh

2012

A&A

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Context. Launched in 1996, HSTOF on board SOHO was the first instrument to detect the energetic neutral atoms (ENA) from the heliosheath. After mid 2003, the field of view of HSTOF was restricted to the flank sectors of the heliosheath, in which region the energetic ion distributions are still unknown. Interpretation of these data requires understanding of the energetic ion transport in the inner heliosheath. Aims. We update the HSTOF ENA hydrogen and helium spectra by adding the results from the recent (2006−2010) measurements. We calculate the energetic ion distributions in a numerical model of the heliosheath and use them as a basis for interpreting the HSTOF ENA observations, in particular those of the flank sectors. Methods. The hydrogen and helium ENA spectra were derived from the HSTOF observations of two 90 • -wide ecliptic longitude sectors around the crosswind directions. The energetic ion distributions in the heliosheath were calculated in a simple model of the heliosphere, assuming that the main acceleration occurs at the termination shock. The effects of different processes (charge-exchange loss, adiabatic acceleration, parallel diffusion and escape across the boundary) were determined with different assumptions about the boundary conditions and the transport parameters. The resulting ion distributions were used to calculate the ENA fluxes, which can be compared with the observations by HSTOF and other instruments. Results. The energetic ion density in the flank sectors of the heliosphere is lower than in the forward (upwind) sector. As a result, the contribution of the flanks of the heliosheath to the production of ENA is not directly proportional to the thickness of the heliosheath, but instead is comparable to the contribution of the forward sector, which agrees with the HSTOF data. The HSTOF ENA flux intensity is nevertheless significantly lower than the model calculations. Near the heliopause there appears a region of low energetic ion density caused by the charge-exchange and the escape losses.

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“…[60] The required energy-dependent charge exchange cross sections, i.e., protons with neutral hydrogen and neutral oxygen, are taken from Barnett [1990], Gruntman [1997], and Lindsay and Stebbings [2005]. Since ion distributions are deconvolved for one energy or energy-range at a time, the charge exchange cross section appears as a multiplicative factor.…”

Section: A2 Physicsmentioning

confidence: 99%

Evolution of CIR storm on 22 July 2009

et al. 2012

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[1] Global images of ion intensities are deconvolved from TWINS ENA images during the main and recovery phase of a CIR storm on 22 July 2009. The global spatial ion images taken at different times, along with solar wind data, geomagnetic activity indices, geosynchronous orbit observations, and in situ measurements from the THEMIS mission provide a picture of the evolution of the ring current during both the main phase and early recovery phase of the storm. Major features of the evolution are consistent with expectations based upon time dependent geomagnetic indices, e.g., SYM/H and ASY/H, and geosynchronous orbit detection of dipolarizations from GOES 11 and 12. Direct comparisons are made with in situ THEMIS ESA and SST spectral measurements. The peak energy of the ion spectrum in the ring current is seen to decrease in the recovery phase. The time evolution of the ion energy spectra over the range from 2.5 to 97.5 keV at the spatial peaks of the ring current in the inner magnetosphere obtained from ENA images is presented for the first time.

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Charge transfer cross sections for energetic neutral atom data analysis

Cited by 301 publications

References 79 publications

Modulation of neutral interstellar He, Ne, O in the heliosphere. Survival probabilities and abundances at IBEX

Modulation of neutral interstellar He, Ne, O in the heliosphere. Survival probabilities and abundances at IBEX

HSTOF ENA observations and energetic ion distributions in the heliosheath

Evolution of CIR storm on 22 July 2009

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