A new model describing Forbush Decreases at Mars: combining the heliospheric modulation and the atmospheric influence

Guo, Jingnan; Wimmer‐Schweingruber, R. F.; Dumbović, Mateja; Heber, B.; Wang, Yuming

doi:10.26464/epp2020007

Cited by 6 publications

(4 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the statistical comparison here suggests that the energy range of the primary GCRs leading to the detected FD may have a larger impact on the FD amplitude, especially when the corresponding energy ranges of the original GCRs are very different at each observer. This highlights the importance of understanding and quantifying the energy-dependent modulation of the GCR particles by solar transients (e.g., Guo et al 2020), enabling the use of FDs to infer the properties of ICMEs.…”

Section: Icme-induced Forbush Decreases On Marsmentioning

confidence: 99%

“…Since the high energy component of the GCRs is less modulated by solar activity, the surface flux is less sensitive to solar modulation conditions than the primary GCR flux is. Guo et al (2020) have modeled this effect using a GEANT4 based model implemented with the Martian atmospheric and regolith properties (as previously used in Guo et al 2018c) and showed that under a given heliospheric modulation potential, the change of GCR rate on the surface of Mars is smaller than that in deep space.…”

Section: Comparison Of Gcr Variations At Earth Ground In Space and On Marsmentioning

confidence: 99%

See 1 more Smart Citation

Radiation environment for future human exploration on the surface of Mars: the current understanding based on MSL/RAD dose measurements

Guo

Zeitlin

Wimmer‐Schweingruber

et al. 2021

Astron Astrophys Rev

Self Cite

View full text Add to dashboard Cite

Potential deleterious health effects to astronauts induced by space radiation is one of the most important long-term risks for human space missions, especially future planetary missions to Mars which require a return-trip duration of about 3 years with current propulsion technology. In preparation for future human exploration, the Radiation Assessment Detector (RAD) was designed to detect and analyze the most biologically hazardous energetic particle radiation on the Martian surface as part of the Mars Science Laboratory (MSL) mission. RAD has measured the deep space radiation field within the spacecraft during the cruise to Mars and the cosmic ray induced energetic particle radiation on Mars since Curiosity’s landing in August 2012. These first-ever surface radiation data have been continuously providing a unique and direct assessment of the radiation environment on Mars. We analyze the temporal variation of the Galactic Cosmic Ray (GCR) radiation and the observed Solar Energetic Particle (SEP) events measured by RAD from the launch of MSL until December 2020, i.e., from the pre-maximum of solar cycle 24 throughout its solar minimum until the initial year of Cycle 25. Over the long term, the Mars’s surface GCR radiation increased by about 50% due to the declining solar activity and the weakening heliospheric magnetic field. At different time scales in a shorter term, RAD also detected dynamic variations in the radiation field on Mars. We present and quantify the temporal changes of the radiation field which are mainly caused by: (a) heliospheric influences which include both temporary impacts by solar transients and the long-term solar cycle evolution, (b) atmospheric changes which include the Martian daily thermal tide and seasonal CO$$_2$$ 2 cycle as well as the altitude change of the rover, (c) topographical changes along the rover path-way causing addition structural shielding and finally (d) solar particle events which occur sporadically and may significantly enhance the radiation within a short time period. Quantification of the variation allows the estimation of the accumulated radiation for a return trip to the surface of Mars under various conditions. The accumulated GCR dose equivalent, via a Hohmann transfer, is about $$0.65 \pm 0.24$$ 0.65 ± 0.24 sievert and $$1.59 \pm 0.12$$ 1.59 ± 0.12 sievert during solar maximum and minimum periods, respectively. The shielding of the GCR radiation by heliospheric magnetic fields during solar maximum periods is rather efficient in reducing the total GCR-induced radiation for a Mars mission, by more than 50%. However, further contributions by SEPs must also be taken into account. In the future, with advanced nuclear thrusters via a fast transfer, we estimate that the total GCR dose equivalent can be reduced to about 0.2 sievert and 0.5 sievert during solar maximum and minimum periods respectively. In addition, we also examined factors which may further reduce the radiation dose in space and on Mars and discuss the many uncertainties in the interpreting the biological effect based on the current measurement.

show abstract

Section: Icme-induced Forbush Decreases On Marsmentioning

confidence: 99%

Section: Comparison Of Gcr Variations At Earth Ground In Space and On Marsmentioning

confidence: 99%

Radiation environment for future human exploration on the surface of Mars: the current understanding based on MSL/RAD dose measurements

Guo

Zeitlin

Wimmer‐Schweingruber

et al. 2021

Astron Astrophys Rev

Self Cite

View full text Add to dashboard Cite

show abstract

“…The amplitude of a FD depends not only on the properties of the heliospheric structure, but also on the energy of the observed GCR particles: lower energy particles are modulated more easily and thus typically show larger FDs (e.g. Lockwood 1971;Lockwood et al 1991;Cane 2000;Guo et al 2020). In the past, the study of FDs was mainly based on data from neutron monitors on the surface of the Earth, but nowadays, GCR measurements suitable for FD studies are also available from many spacecraft in the near-Earth space as well as on other solar system bodies, and these have been routinely used for multi-spacecraft studies (e.g.…”

Section: Introductionmentioning

confidence: 99%

Radial Evolution of the April 2020 Stealth Coronal Mass Ejection between 0.8 and 1 AU -- A Comparison of Forbush Decreases at Solar Orbiter and Earth

von Forstner,

Dumbović,

Möstl

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

Aims. We present observations of the first coronal mass ejection (CME) observed at the Solar Orbiter spacecraft on April 19, 2020, and the associated Forbush decrease (FD) measured by its High Energy Telescope (HET). This CME is a multispacecraft event also seen near Earth the next day. Methods. We highlight the capabilities of HET for observing small short-term variations of the galactic cosmic ray count rate using its single detector counters. The analytical ForbMod model is applied to the FD measurements to reproduce the Forbush decrease at both locations. Input parameters for the model are derived from both in situ and remote-sensing observations of the CME. Results. The very slow (∼ 350 km/s) stealth CME caused a FD with an amplitude of 3 % in the low-energy cosmic ray measurements at HET and 2 % in a comparable channel of the Cosmic Ray Telescope for the Effects of Radiation (CRaTER) on the Lunar Reconnaissance Orbiter, as well as a 1 % decrease in neutron monitor measurements. Significant differences are observed in the expansion behavior of the CME at different locations, which may be related to influence of the following high speed solar wind stream. Under certain assumptions, ForbMod is able to reproduce the observed FDs in low-energy cosmic ray measurements from HET as well as CRaTER, but with the same input parameters, the results do not agree with the FD amplitudes at higher energies measured by neutron monitors on Earth. We study these discrepancies and provide possible explanations. Conclusions. This study highlights that the novel measurements of the Solar Orbiter can be coordinated with other spacecraft to improve our understanding of space weather in the inner heliosphere. Multi-spacecraft observations combined with data-based modeling are also essential to understand the propagation and evolution of CMEs as well as their space weather impacts.

show abstract

“…It should be noted that there are other approaches to FD modelling in the FR, such as perpendicular transport by guiding centre drifts (e.g. Krittinatham & Ruffolo 2009;Tortermpun et al 2018), full trajectory integration using CME FR-type models (Petukhova et al 2019), or CME magnetic field reconstructions from in situ measurements (Benella et al 2020), as well as describing FDs via the change in the single GCR spectrum modulation parameter attributed with a CME (Guo et al 2020). However, a recent study by Laitinen & Dalla (2021), in which they performed full-orbit particle simulations, with the interface between the external interplanetary magnetic field and the isolated FR field lines modelled analytically, revealed that the transport around the FR border is fast compared to diffusive radial propagation within the FR.…”

Section: Introductionmentioning

confidence: 99%

A new method of measuring Forbush decreases

Dumbović,

Kramarić,

Benko

et al. 2024

A&A

View full text Add to dashboard Cite

Forbush decreases (FDs) are short-term depressions in the galactic cosmic ray (GCR) flux and one of the common signatures of coronal mass ejections (CMEs) in the heliosphere. They often show a two-step profile, the second one associated with the CME's magnetic structure. This second step can be described by the recently developed analytical FD model for flux ropes (FRs) --ForbMod. The aim of this study is to utilise ForbMod to develop a best-fit procedure to be applied on FR-related FDs as a convenient measurement tool. Our motivation is to develop a best-fit procedure that can be applied to a data series from an arbitrary detector. Thus the basic procedure would facilitate measurement estimation of the magnitude of the FR-related FD with the possibility of being adapted for the energy response of a specific detector for a more advanced analysis. The non-linear fitting was performed by calculating all possible ForbMod curves constrained within the FR borders to the designated dataset and minimising the mean square error (MSE). In order to evaluate the performance of the ForbMod best-fit procedure, we used synthetic measurements produced by calculating the theoretical ForbMod curve for a specific example CME and then applying various effects to the data to mimic the imperfection of the real measurements. We also tested the ForbMod best-fit function on the real data, measured by detector F of the SOHO/EPHIN instrument on a sample containing 30 events, all of which have a distinct FD corresponding to the magnetic obstacle (MO). The extraction of FD profiles (from the onset to the end) was performed manually by an observer, whereby we applied two different versions of border selection and assigned a quality index to each event. We do not find notable differences between events marked by a different quality index. For events with a selection of two different borders, we find that the best fit applied on extended interplanetary coronal mass ejection (ICME) structure borders results in a slightly larger MSE and differences compared to the traditional method due to a larger scatter of the data points. We find that the best-fit results can visually be categorised into six different FD profile types. Although some profiles do not show a visually pleasing FD, the ForbMod best-fit function still manages to find a solution with a relatively small MSE. Overall, we find that the ForbMod best-fit procedure performs similar to the traditional algorithm-based observational method, but with slightly smaller values for the FD amplitude, as it's taking into account the noise in the data. Furthermore, we find that the best-fit procedure has an advantage compared to the traditional method as it can estimate the FD amplitude even when there is a data gap at the onset of the FD.

show abstract

A new model describing Forbush Decreases at Mars: combining the heliospheric modulation and the atmospheric influence

Cited by 6 publications

References 44 publications

Radiation environment for future human exploration on the surface of Mars: the current understanding based on MSL/RAD dose measurements

Radiation environment for future human exploration on the surface of Mars: the current understanding based on MSL/RAD dose measurements

Radial Evolution of the April 2020 Stealth Coronal Mass Ejection between 0.8 and 1 AU -- A Comparison of Forbush Decreases at Solar Orbiter and Earth

A new method of measuring Forbush decreases

Contact Info

Product

Resources

About