Tsutomu Nagatsuma
(NICT, Japan)

Disturbances of Space environment around the Earth (geospace) is controlled by the activity of the Sun and the solar wind. Disturbances in geospace sometimes cause serious problems to satellites, astronauts, and telecommunications. To minimize the effect of the problems, space weather forecasting is necessary. In Japan, NICT (National Institute of Information and Communications Technology) is in charge of space weather forecasting services as a regional warning center of International Space Environment Service. With help of geospace environment data exchanging among the international cooperation, NICT operates daily space weather forecast service every day to provide information on nowcasts and forecasts of solar flare, geomagnetic disturbances, solar proton event, and radio-wave propagation conditions in the ionosphere. For prompt reporting of space weather information, we also conduct our original observation networks from the Sun to the upper atmosphere: Hiraiso solar observatory, domestic ionosonde networks, magnetometer & HF radar observations in far-east Siberia and Alaska, and south-east Asia low-latitude ionospheric network (SEALION). ACE and STEREO real-time beacon data are received using our antenna facilities to monitor the solar and solar wind conditions in near real-time. Our current activities and future perspective of space weather monitoring and forecasting will be introduced in this talk.

Takahiro Obara
(JAXA, Japan)

In order to investigate space environment and its temporal variation, JAXA Space Environment Group has been conducting space environment measurements for more than 20 years. JAXA installed radiation particle detectors, magnetometers and plasma detectors on LEO satellites, GEO satellites, GTO satellites and Quasi zenith orbiting satellite. With these data, some distinguished sciences of energetic electron environment have been obtained. Intensity of highly energetic (MeV) electrons in the outer radiation belt seems to be controlled by solar wind velocity as well as magnetic activities. With these relations, we have constructed advanced outer radiation belt model and assessed radiation belt models. Transport of intermediate energy (100keV) electrons from the plasmasheet into the outer belt zone was identified, which seems to lead a large enhancement of highly energetic (MeV) electrons in the outer radiation belt. It was also found that energetic electrons penetrated into the inner belt across the slot region during the very big magnetic storms. We have newly found that low energy (less than 30keV) electrons have been being transported very frequently to very near Earth region; i.e. a few thousand km above sea level. We will explain details with some simulation results to interpret observations.

Minoru Iwata
(Kyushu Institute of Technology, Japan)

The atomic oxygen (AO) on low earth orbit erodes spacecraft materials. Since the organic materials are damaged by atomic oxygen, significantly, we must evaluate the erosion effects during satellite mission duration before launch. The first thing that is necessary to evaluate the erosion effect due to atomic oxygen is to know the distribution of atomic oxygen fluence and/or flux on entire satellite surface during satellite mission duration. The atomic oxygen fluence on the satellite surface is different for the different part of satellite surface because ram surface receiving atomic oxygen changes with satellite attitude on orbit. Therefore, atomic oxygen fluence must be estimated by considering satellite attitude, shape, ram direction, and AO density at orbit. However, there is no analysis report in which the AO fluence distribution is estimated on entire satellite surface. In addition to this, there is no analysis tool of AO fluence distribution on satellite surface. In this study, we construct AO fluence distribution analysis tool and estimate the AO fluence distribution on entire satellite surface. The detail of analysis results would be presented in symposium.