Refine your search:     
Report No.
 - 
Search Results: Records 1-14 displayed on this page of 14
  • 1

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Nowcast and forecast of galactic cosmic ray (GCR) and solar energetic particle (SEP) fluxes in magnetosphere and ionosphere; Extension of WASAVIES to earth orbit

Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Miyoshi, Yoshizumi*; Ueno, Haruka*; Nagamatsu, Aiko*

Journal of Space Weather and Space Climate (Internet), 9, p.A9_1 - A9_11, 2019/03

Real-time estimation of astronaut doses during solar particle events (SPE) is one of the most challenging tasks in cosmic-ray dosimetry. We therefore develop a new computational method that can nowcast the solar energetic particle (SEP) as well as galactic cosmic-ray (GCR) fluxes on any Earth orbit during a large SPE associating with ground level enhancement. It is an extended version of WArning System for AVIation Exposure to Solar Energetic Particle, WASAVIES. The extended version, called WASAVIES-EO, can calculate the GCR and SEP fluxes outside a satellite based on its two-line element data. Moreover, organ dose and dose-equivalent rates of astronauts in the International Space Station (ISS) can be estimated using the system, considering its shielding effect. The accuracy of WASAVIES-EO was validated based on the dose rates measured in ISS, as well as based on high-energy proton fluxes observed by POES satellites.

Journal Articles

Comparison of cosmic-ray environments on earth, moon, mars and in spacecraft using PHITS

Sato, Tatsuhiko; Nagamatsu, Aiko*; Ueno, Haruka*; Kataoka, Ryuho*; Miyake, Shoko*; Takeda, Kazuo*; Niita, Koji*

Radiation Protection Dosimetry, 180(1-4), p.146 - 149, 2018/08

 Times Cited Count:1 Percentile:38.14(Environmental Sciences)

Cosmic-ray dose rates spatially and temporally change very much. In this study, we compared the calculated cosmic-ray environments on the Earth, Moon, and Mars as well as inside spacecraft on low-earth orbit (LEO) and at interplanetary space. In the calculation, a galactic cosmic-ray model developed in DLR and trapped proton/electron models AP9/AE9 were used for determining the incident cosmic-ray fluxes, and the Particle and Heavy Ion Transport code System, PHITS, was employed for the cosmic-ray transport simulation in the Earth, Lunar, and Martian systems as well as spacecraft. The virtual International Space Station (ISS) model developed by JAXA was adopted as the representative of spacecraft in the PHITS simulation. This paper focuses on the comprehensive discussions on the difference of cosmic-ray environments and the effective methods of their shielding in various exposure situations.

Journal Articles

Radiation dose nowcast for the ground level enhancement on 10-11 September 2017

Kataoka, Ryuho*; Sato, Tatsuhiko; Miyake, Shoko*; Shiota, Daiko*; Kubo, Yuki*

Space Weather, 16(7), p.917 - 923, 2018/07

 Times Cited Count:8 Percentile:2.3(Astronomy & Astrophysics)

A ground level enhancement (GLE) event occurred on 10-11 September 2017, associated with X8.2 solar flare exploded at western limb. The magnitude of the GLE was not so large even at the peak, but the duration of the event was longer than average. We briefly report the results of our manually conducted nowcast using WASAVIES (Warning System of AViation Exposure to Solar energetic particles). The maximum radiation dose rate at 12 km flight altitude was estimated to be approximately 2 $$mu$$Sv/h, which is only one-third of the corresponding background dose rate due to the galactic cosmic-ray exposure. This result verified the safety of aircrews and passengers in aviation during this event.

Journal Articles

Real time and automatic analysis program for WASAVIES; Warning system for aviation exposure to solar energetic particles

Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*

Space Weather, 16(7), p.924 - 936, 2018/07

 Times Cited Count:4 Percentile:11.05(Astronomy & Astrophysics)

A physics-based warning system of aviation exposure to solar energetic particles, WASAVIES, is improved to be capable of real-time and automatic analysis. In the improved system, the count rates of several neutron monitors (NM) at the ground level, as well as the proton fluxes measured by the GOES satellite are continuously downloaded at intervals of 5 min and used for determining the model parameters. The performance of WASAVIES is examined by analyzing the three major GLE events of the 21st century. A web-interface of WASAVIES is also developed and will be released in the near future through the public server of NICT.

Journal Articles

Cosmic ray modulation and radiation dose of aircrews during the solar cycle 24/25

Miyake, Shoko*; Kataoka, Ryuho*; Sato, Tatsuhiko

Space Weather, 15(4), p.589 - 605, 2017/04

 Times Cited Count:6 Percentile:23.92(Astronomy & Astrophysics)

Weak solar activity and high cosmic-ray flux during the coming solar cycle are qualitatively anticipated by the recent observation that show the decline in the solar activity levels. We have quantitatively predicted the cosmic-ray modulation and resultant radiation exposure at flight altitude by using the time-dependent and three dimensional model of the cosmic-ray modulation. The database of airshower simulation performed by Particle and Heavy Ion Transport code System, PHITS, was employed in the prediction. Our predictions of the neutron monitor counting rate and the radiation dose of aircrews during the solar cycle 24/25 have some natures caused by the charge sign dependence of the cosmic-ray modulation, such as the flat-top profiles.

Oral presentation

Cosmic-ray dosimetry based on the PHITS code

Sato, Tatsuhiko; Nagamatsu, Aiko*; Ueno, Haruka*; Kataoka, Ryuho*; Miyake, Shoko*; Takeda, Kazuo*; Niita, Koji*

no journal, , 

We are developing the computational dosimetry system used for cosmic-ray exposure, based on the Particle and Heavy Ion Transport code System PHITS. In the system, cosmic-ray environments outside spacecraft are estimated from the JAXA's space-radiation environment model, while cosmic-ray environments inside spacecraft are determined from the PHITS simulation. The details of the system will be presented at the meeting.

Oral presentation

Current states and future needs on the Warning System for Aviation Exposure to Solar Energetic Particle (WASAVIES)

Sato, Tatsuhiko; Kataoka, Ryuho*; Yasuda, Hiroshi*; Kubo, Yuki*; Ishii, Mamoru*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*

no journal, , 

Estimation of radiation doses for astronauts as well as aircrews due to the exposure to solar energetic particles (SEP) is one of the greatest challenges in space weather research. We are therefore developing a WArning System for AVIation Exposure to Solar energetic particle (WASAVIES), under the framework of Project for Solar-Terrestrial Environment Prediction (PSTEP). In the system, the SEP fluxes incident to the atmosphere are calculated by physics-based models. Thus, WASAVIES can estimate not only the current value but also time variation of the aircrew doses after a GLE event occurs. A brief outline of WASAVIES together with the status of on-going research subjects such as development of the automatic calculation algorithm will be presented at the meeting.

Oral presentation

Warning system for aviation exposure to solar energetic particle (WASAVIES)

Sato, Tatsuhiko; Kataoka, Ryuho*; Yasuda, Hiroshi*; Kubo, Yuki*; Ishii, Mamoru*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*

no journal, , 

Estimation of radiation doses for astronauts as well as aircrews due to the exposure to solar energetic particles (SEP) is one of the greatest challenges in space weather research. We are therefore developing a WArning System for AVIation Exposure to Solar energetic particle (WASAVIES), under the framework of Project for Solar-Terrestrial Environment Prediction (PSTEP). In the system, the radiation doses due to SEP exposure at flight altitudes are calculated on the basis of physics-based models and databases with four free parameters, which express the absolute value, power index, and time profiles of SEP fluxes near the sun, and the pitch angle incident to the magnetosphere. Thus, WASAVIES can estimate not only the current value but also time variation of the aircrew doses after a GLE event occurs. A brief outline of WASAVIES together with the status of on-going research subjects such as development of the web-based nowcast and forecast system will be presented at the meeting.

Oral presentation

Radiation dose estimation during the ground level enhancement on 10-11 September 2017 using WASAVIES

Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Tsujino, Takashi*

no journal, , 

A ground level enhancement (GLE) event occurred on 10-11 September 2017, associated with X8.2 solar flare exploded at western limb. The magnitude of the GLE was not so large even at the peak, but the duration of the event was longer than average. We briefly report the results of our manually conducted nowcast using WASAVIES (Warning System of AViation Exposure to Solar energetic particles). The maximum radiation dose rate at 12 km flight altitude was estimated to be approximately 2 $$mu$$Sv/h, which is only one-third of the corresponding background dose rate due to the galactic cosmic-ray exposure. This result verified the safety of aircrews and passengers in aviation during this event. The automatic calculation system of WASAVIES was developed, and it will be released via website of Regional Warning Center Japan, International Space Environment Services (RWC Japan, ISES) at NICT in near future.

Oral presentation

WASAVIES: Warning system for aviation exposure to solar energetic particles

Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*

no journal, , 

A physics-based warning system for aviation exposure to solar energetic particles, WASAVIES, is developed for nowcasts and forecasts the radiation dose rates all over the world up to 24 h after the large solar flare onset. The performance of WASAVIES is examined by analyzing the three major GLE events of the 21st century. The accuracy of the calculated dose rates is well validated by the reproducibility of the count rates of several neutron monitors and GOES proton fluxes. A web-interface of WASAVIES is also developed and will be released in the near future through the public server of NICT.

Oral presentation

Current status of WASAVIES: Warning system for aviation exposure to solar energetic particles

Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*

no journal, , 

We are developing a physics-based warning system for aviation exposure to solar energetic particles, WASAVIES, under the framework of the PSTEP project in Japan. It can nowcast and forecast the radiation dose rates all over the world up to 24 h after the large solar flare onset. The performance of WASAVIES is examined by analyzing the three major GLE events of the 21st century. The accuracy of the calculated dose rates is well validated by the reproducibility of the count rates of several neutron monitors and GOES proton fluxes. A web-interface of WASAVIES is also developed and will be released in the near future through the public server of NICT.

Oral presentation

Real-time estimation of astronaut doses during large solar particle events based on WASAVIES

Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*; Ueno, Haruka*; et al.

no journal, , 

Real-time estimation of astronaut doses during solar particle events (SPE) is one of the most challenging tasks in cosmic-ray dosimetry. We therefore develop a new computational method that can nowcast the solar energetic particle (SEP) as well as galactic cosmic-ray (GCR) fluxes on any Earth orbit during a large SPE associating with ground level enhancement. It is an extended version of WArning System for AVIation Exposure to Solar Energetic Particle, WASAVIES. The detailed calculation procedures of WASAVIES-EO will be presented at the meeting, together with the results of its validation based on the experimental data measured in ISS during GLE60, 71 and 72.

Oral presentation

Recent improvement of WASAVIES; Warning system for aviation exposure to solar energetic particle

Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Miyoshi, Yoshizumi*

no journal, , 

We are developing a physics-based warning system for aviation exposure to solar energetic particles, WASAVIES, under the framework of the PSTEP project in Japan. It can nowcast and forecast the radiation dose rates all over the world up to 24 h after the large solar flare onset. The performance of WASAVIES is examined by analyzing the three major GLE events of the 21st century. The accuracy of the calculated dose rates is well validated by the reproducibility of the count rates of several neutron monitors and GOES proton fluxes. In this presentation, we will explain details of the web-interface of WASAVIES, which will be released in the near future through the public server of NICT.

Oral presentation

Current status of WASAVIES; Warning system for aviation exposure to solar energetic particles

Sato, Tatsuhiko; Kataoka, Ryuho*; Shiota, Daiko*; Kubo, Yuki*; Ishii, Mamoru*; Yasuda, Hiroshi*; Miyake, Shoko*; Park, I.*; Miyoshi, Yoshizumi*

no journal, , 

We are developing a physics-based warning system for aviation exposure to solar energetic particles, WASAVIES, under the framework of the PSTEP project in Japan. It can nowcast and forecast the radiation dose rates all over the world up to 24 h after the large solar flare onset. The performance of WASAVIES is examined by analyzing the three major GLE events of the 21st century. The accuracy of the calculated dose rates is well validated by the reproducibility of the count rates of several neutron monitors and GOES proton fluxes. A web-interface of WASAVIES is also developed and will be released from March 2019 through the public server of NICT.

14 (Records 1-14 displayed on this page)
  • 1