An Empirical Modification of the Force Field Approach to Describe the Modulation of Galactic Cosmic Rays Close to Earth in a Broad Range of Rigidities

Gieseler, J.; Heber, Bernd; Herbst, K.

doi:10.1002/2017ja024763

Cited by 58 publications

(41 citation statements)

References 56 publications

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“…Since we have shown that the calculated dose rate is rather insensitive to the actual value of / (Fig. 5) and since the topic being discussed focuses on discussing measurement principles, rather than predicting future absorbed dose rates, we will use the / PP by Gieseler et al (2017)…”

Section: Generating a Time Series And Comparing With Datamentioning

confidence: 99%

Galactic Cosmic Ray induced absorbed dose rate in deep space – Accounting for detector size, shape, material, as well as for the solar modulation

Banjac

Berger

Burmeister

et al. 2019

J. Space Weather Space Clim.

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Depending on the radiation field, the absorbed dose rate can depend significantly upon the size of the detectors or the phantom used in the models. In deep space (interplanetary medium) the radiation field is on avarage dominated by Galactic Cosmic Ray (GCR) nuclei. Here, the deep space dose rate that a typical small silicon slab detector measures is compared to a larger phantom corresponding to an ICRU sphere with a 15 cm radius composed of water. To separate and understand respective effects from the composition, size and shape differences in the detectors, this comparison is implemented in several steps. For each phantom, the absorbed dose rate due to GCR nuclei up to Z = 28, as a function of solar modulation conditions, is calculated. The main components of the GCR flux are protons, followed by helium nuclei and electrons, with Z > 2 nuclei accounting for approximately 1% of the total number of particles. Among the light nuclei with Z > 2, most abundant ones are C, N and O. In this study, we use the GEANT4 model to calculate the absorbed dose (energy deposited as ionization, divided by mass) due to the GCR flux provided by the Badhwar-O’Neill 2010 (BON-10) model. Furthermore, we investigate how the determined absorbed dose rate changes throughout the solar cycle by varying the GCR models from solar minimum to solar maximum conditions. The developed model is validated against the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) microdosimeter measurements. In our current approach, we do not consider the effects of shielding, which will always be present under realistic scenarios. A second goal of this study is to quantify the contribution of each Z = 1, …, 28 GCR nuclei to absorbed dose rate, in relation to the phantom characteristics. For each Z we determine the most relevant energy range in the GCR spectra for absorbed dose rate estimations. Furthermore, we calculate a solar modulation dependent conversion factor to convert absorbed dose rate measured in silicon to absorbed dose rate in water. This information will improve our understanding of the radiation environment due to GCR in the near-Earth deep space and also benefit further modeling efforts by limiting the number and energy range of primary particle species that have to be considered.

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Section: Generating a Time Series And Comparing With Datamentioning

confidence: 99%

Galactic Cosmic Ray induced absorbed dose rate in deep space – Accounting for detector size, shape, material, as well as for the solar modulation

Banjac

Berger

Burmeister

et al. 2019

J. Space Weather Space Clim.

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“…However, the approach, among others, neglects adiabatic cooling processes and can depend on additional parameters such as the magnetic field structure, particle drifts, stellar cycle, etc. (Gieseler et al 2017, and references therein). Thus, an application of the FFA to other stars requires knowledge of the astrospheric turbulence (represented by κ) as well as the stellar wind velocity.…”

Section: Introductionmentioning

confidence: 99%

A new model suite to determine the influence of cosmic rays on (exo)planetary atmospheric biosignatures

Herbst

Grenfell

Sinnhuber

et al. 2019

A&A

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Context. The first opportunity to detect indications for life outside the Solar System may be provided already within the next decade with upcoming missions such as the James Webb Space Telescope (JWST), the European Extremely Large Telescope (E-ELT) and/or the Atmospheric Remote-sensing Infrared Exoplanet Large-survey (ARIEL) mission, searching for atmospheric biosignatures on planets in the habitable zone of cool K-and M-stars. Nevertheless, their harsh stellar radiation and particle environment could lead to photochemical loss of atmospheric biosignatures. Aims. We aim to study the influence of cosmic rays on exoplanetary atmospheric biosignatures and the radiation environment considering feedbacks between energetic particle precipitation, climate, atmospheric ionization, neutral and ion chemistry, and secondary particle generation. Methods. We describe newly-combined state-of-the-art modeling tools to study the impact of the radiation and particle environment, in particular of cosmic rays, on atmospheric particle interaction, the influence on the atmospheric chemistry and the climate-chemistry coupling in a self-consistent model suite. To this end, models like the Atmospheric Radiation Interaction Simulator (AtRIS), the Exoplanetary Terrestrial Ion Chemistry model (ExoTIC), and the updated coupled climate-chemistry model are combined. Results. Besides comparing our results to Earth-bound measurements, we investigate the ozone-production and -loss cycles as well as the atmospheric radiation dose profiles during quiescent solar periods and during the strong solar energetic particle event of February 23, 1956. Further, the scenario-dependent terrestrial transit spectra, as seen by the NIR-Spec infrared spectrometer onboard the JWST, are modeled. Amongst others, we find that the comparatively weak solar event (i) drastically increases the spectral signal of HNO 3 , while (ii) significantly suppressing the spectral feature of ozone. Because of the slow recovery after such events, the latter indicates that ozone might not be a good biomarker for planets orbiting stars with high flaring rates.

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“…We will validate our results against three of the published measurements performed on 16 April 1965, on 29 July 1967, and on 2 August 1969 (values given in their Table 4). Based on the LIS by Herbst et al () and the modified modulation parameter ϕ by Gieseler et al () the following corresponding ϕ values were used: ϕ 1965 = 380 MV, ϕ 1967 = 665 MV, and ϕ 1969 = 950 MV. For helium, the modulation parameter was one half of the proton ϕ .…”

Section: Validationmentioning

confidence: 99%

“…In order to validate against Earth measurements, AtRIS was used with atmospheres generated using the NRLMSISE-00 model (Picone et al, 2002), using all available gas species (N, N 2 , O, O 2 , Ar, He, and H). Primary spectra were obtained by following the modified force field approach outlined in Gieseler et al (2017) based on the LIS model by Burger et al (2000), Herbst et al (2017), Usoskin et al (2011), and references therein. For each validation case, we provide the modulation parameters that have been used.…”

Section: Validationmentioning

confidence: 99%

The Atmospheric Radiation Interaction Simulator (AtRIS): Description and Validation

2019

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We present the Atmospheric Radiation Interaction Simulator (AtRIS), a newly developed GEANT4‐based code tailored specifically to enable parametric studies of radiation propagation through various (exo)planetary atmospheres. Its main purpose is to model the altitude‐dependent atmospheric secondary particle environment and to calculate the ion pair production rates, which are a mandatory input for atmospheric chemistry models in order to, for example, directly characterize the habitability of the modeled planet. Similar codes have been developed previously (e.g., PLANETOCOSMICS; Desorgher, et al., ); however, until now, none possesses the necessary flexibility in the specification of the atmosphere and the regolith that is necessary to model planets outside our solar system. Here we provide a detailed description of AtRIS and its validation against earthbound measurements. For validation, we show comparisons against Earth measurements. Thereby, the focus is on the atmospheric altitude‐dependent ionization, the surface muon, and the neutron fluxes, as well as the primary proton fluxes. Furthermore, a comparison of the computed energy losses of monoenergetic protons based on AtRIS and PLANETOCOSMICS is shown. Our aim is to demonstrate the validity of AtRIS and its importance for future studies on, for example, potential (Earth‐like) exoplanets.

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An Empirical Modification of the Force Field Approach to Describe the Modulation of Galactic Cosmic Rays Close to Earth in a Broad Range of Rigidities

Cited by 58 publications

References 56 publications

Galactic Cosmic Ray induced absorbed dose rate in deep space – Accounting for detector size, shape, material, as well as for the solar modulation

Galactic Cosmic Ray induced absorbed dose rate in deep space – Accounting for detector size, shape, material, as well as for the solar modulation

A new model suite to determine the influence of cosmic rays on (exo)planetary atmospheric biosignatures

The Atmospheric Radiation Interaction Simulator (AtRIS): Description and Validation

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