Search Publications
Solar and geomagnetic activity dependence of 150-km echoes observed by the Equatorial Atmosphere Radar in Indonesia
Yokoyama, Tatsuhiro; Takagi, Rieko; Yamamoto, Mamoru
The occurrence characteristics of 150-km echoes in low-latitude regions are studied using the Equatorial Atmosphere Radar (EAR) in Indonesia. The long-term observation of the 150-km echoes by the EAR enables us to study the occurrence characteristics of 150-km echoes statistically. It is shown that the occurrence rate of the 150-km echoes observed…
Validation of coronal mass ejection arrival-time forecasts by magnetohydrodynamic simulations based on interplanetary scintillation observations
Tokumaru, Munetoshi; Fujiki, Ken'ichi; Shiota, Daikou +3 more
Coronal mass ejections (CMEs) cause various disturbances of the space environment; therefore, forecasting their arrival time is very important. However, forecasting accuracy is hindered by limited CME observations in interplanetary space. This study investigates the accuracy of CME arrival times at the Earth forecasted by three-dimensional (3D) ma…
Relationship between three-dimensional velocity of filament eruptions and CME association
Ichimoto, Kiyoshi; Ishii, Takako T.; Asai, Ayumi +2 more
It is widely recognised that filament disappearances or eruptions are frequently associated with Coronal Mass Ejections (CMEs). Since CMEs are a major source of disturbances of the space environment surrounding the Earth, it is important to investigate these associations in detail for the better prediction of CME occurrence. However, the proportio…
Unusual enhancement of 30 MeV proton flux in an ICME sheath region
Yashiro, Seiji; Nitta, Nariaki V.; Oka, Mitsuo +3 more
In gradual Solar Energetic Particle (SEP) events, shock waves driven by coronal mass ejections (CMEs) play a major role in accelerating particles, and the energetic particle flux enhances substantially when the shock front passes by the observer. Such enhancements are historically referred to as Energetic Storm Particle (ESP) events, but it remain…
The total failures of GPS functioning caused by the powerful solar radio burst on December 13, 2006
Afraimovich, E. L.; Demyanov, V. V.; Smolkov, G. Ya.
We investigated failures in the GPS performance produced by extremely dense solar radio burst fluxes associated with the intense (X3.4 in GOES classification) solar flare and Halo CME recorded by SOHO/LASCO on December 13, 2006. According to substantial experimental evidence, high-precision GPS positioning on the entire sunlit side of the Earth wa…
Determination of the magnetic loop configuration of a solar flare
Sakurai, T.; Hanaoka, Y.
Observationally derived three-dimensional magnetic loop structures of solar flares tell us what type of magnetic configurations is actually responsible for the reconnection/energy release in solar flares. So far, the loop configuration has been discussed on a rather schematic basis, because of insufficient data coverage. However, now we have data …