The space-developed dynamic vertical cutoff rigidity model and its applicability to aircraft radiation dose

Smart, D. F.; Shea, M. A.

doi:10.1016/s0273-1177(03)90376-0

Cited by 36 publications

(33 citation statements)

References 7 publications

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“…Comparisons between satellite-derived rigidity cutoffs and those determined by particle tracing studies generally show the measured cutoff latitudes are several degrees lower than the theoretical values [e.g., Fanselow and Stone, 1972]. However, new calculations undertaken using improved geomagnetic field models have resulted in lower rigidity-determined latitude cutoffs than earlier particle tracing studies [e.g., Smart and Shea, 2003a], improving this comparison.…”

Section: Introductionmentioning

confidence: 85%

Dynamic geomagnetic rigidity cutoff variations during a solar proton event

et al. 2006

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[1] Solar proton events (SPE) are major, though infrequent, space weather phenomena that can produce hazardous effects in the near-Earth space environment. A detailed understanding of their effects depends upon knowledge of the dynamic rigidity cutoffs imposed by the changing total magnetic field. For the first time we investigate detailed comparisons between theoretical cutoff rigidities and ground-based measurements during the large geomagnetic disturbance of 4-10 November 2001. We make use of the imaging riometer (IRIS) at Halley, Antarctica, fortunately situated such that the rigidity cutoff sweeps back and forth across the instrument's field of view during the SPE period. The K p -dependent geomagnetic rigidity cutoff energies are determined from satellite observations combined with previously reported particle-tracing results. We find that the predicted absorption levels show good agreement with those experimentally observed for low and middle levels of geomagnetic disturbance (K p < 5). However, during more disturbed geomagnetic conditions the cutoff modeling overestimates the stretching of the geomagnetic field, underestimating the rigidity cutoff energies, and hence leading to riometer absorption predictions that are too high. In very disturbed conditions (K p % 7-9) the rigidity energy cutoffs indicated by the IRIS observations appear to be equivalent to those predicted for K p % 6 by the particle-tracing approach. Examples of changing rigidity cutoff contours for increasing levels of geomagnetic disturbance are presented.

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Section: Introductionmentioning

confidence: 85%

Dynamic geomagnetic rigidity cutoff variations during a solar proton event

et al. 2006

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“…Significant deviations of the modeling results from the observations can be seen during the first 24 hours of the event. This may be due to >500 km of the path being influenced by precipitation during some of this period because of geomagnetic disturbances [Smart and Shea, 2003], and asymmetry in particle precipitation around the geomagnetic pole at the start of the event [Krimgis and Van Allen, 1967].…”

Section: Partial Polar Pathsmentioning

confidence: 99%

Modeling polar ionospheric effects during the October–November 2003 solar proton events

et al. 2006

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[1] At Ny Å lesund, Svalbard (78°54 0 N, 11°53 0 E, L $ 18), a narrowband VLF receiver was used to monitor the behavior of the amplitude of several high-power transmitters located in the Northern Hemisphere under the influence of the solar proton events (SPE) of October/November 2003. We have used Sodankylä ion chemistry (SIC) atmospheric model profiles calculated at the midpoint location of the propagation paths in the northern wintertime polar region to investigate the radio propagation properties of several highlatitude paths. Different paths showed different responses to the proton precipitation, but propagation modeling was broadly able to account for most of the positive and negative responses observed. Using the SIC-based electron density profiles, we have been able to develop models of ionospheric effective height (h 0 ) and sharpness (b) in order to describe the D region behavior as a function of proton flux, extending previous work which reported b and h 0 values as functions of the X-ray flux from solar flares. As a result of these models, our understanding of VLF propagation influenced by SPEs is such that VLF observations might be used to predict changes in the ionospheric D region electron density profiles during other particle precipitation events.

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“…They may also be used to predict the polar cap absorption (PCA) effects (Dmitriev et al, 2010) during the geomagnetic storms. The aircraft radiation dose can also be calculated with a similar method which was adopted by Smart and Shea (2003b); Mertens et al (2008Mertens et al ( , 2010 and so on.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…where v is the initial velocity of particles, and the altitude of the position is set to be 450 km as the initial position according to Smart and Shea (2003b). In addition, the inner boundary is set to be 1.0 R E from the Earth center, and the outer boundary is the magnetopause determined by the subroutine T96-MGNP-08 in the GEOPACK-2008 (Tsyganenko, 1995) package.…”

Section: Models and Methodsmentioning

confidence: 99%

The geomagnetic cutoff rigidities at high latitudes for different solar wind and geomagnetic conditions

Chu

Qin

2016

Ann. Geophys.

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Abstract. Studying the access of the cosmic rays (CRs) into the magnetosphere is important to understand the coupling between the magnetosphere and the solar wind. In this paper we numerically studied CRs' magnetospheric access with vertical geomagnetic cutoff rigidities using the method proposed by Smart and Shea (1999). By the study of CRs' vertical geomagnetic cutoff rigidities at high latitudes we obtain the CRs' window (CRW) whose boundary is determined when the vertical geomagnetic cutoff rigidities drop to a value lower than a threshold value. Furthermore, we studied the area of CRWs and found out they are sensitive to different parameters, such as the z component of interplanetary magnetic field (IMF), the solar wind dynamic pressure, AE index, and Dst index. It was found that both the AE index and Dst index have a strong correlation with the area of CRWs during strong geomagnetic storms. However, during the medium storms, only AE index has a strong correlation with the area of CRWs, while Dst index has a much weaker correlation with the area of CRWs. This result on the CRW can be used for forecasting the variation of the cosmic rays during the geomagnetic storms.

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The space-developed dynamic vertical cutoff rigidity model and its applicability to aircraft radiation dose

Cited by 36 publications

References 7 publications

Dynamic geomagnetic rigidity cutoff variations during a solar proton event

Dynamic geomagnetic rigidity cutoff variations during a solar proton event

Modeling polar ionospheric effects during the October–November 2003 solar proton events

The geomagnetic cutoff rigidities at high latitudes for different solar wind and geomagnetic conditions

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