Engineering topics

Kozuka, Y.

Publications and source records attributed to Kozuka, Y..

3 records

NASA NTRS1992

Disturbances of both cometary and Earth's magnetospheres excited by single solar flares

In the solar wind a comet plays the role of a windvane that moves three-dimensionally in the heliomagnetosphere. Among the solar systems bodies, only comets have a wide range of inclination angles of their orbital planes to the ecliptic plane ranging from 0 to 90 deg. Therefore, observations of cometary plasma tails are useful in probing the heliomagnetospheric conditions in the high heliolatitudinal region. A comet can be compared to a polar-orbiting probe encircling the Sun. We will introduce two rare cases in which the magnetospheres of both the comet and the Earth are disturbed by a single solar flare.

Konno, I.↗

NASA NTRS1991

The source surface and photospheric magnetic field models

It is possible to reproduce the configuration of the neutral line on the solar source surface by the axial dipole at the center of the sun and a few fictitious dipoles on the photosphere. An attempt is made to identify the nature of such fictitious dipoles in the photospheric magnetic fields. It is shown that large-scale photospheric dipole fields can be identified clearly at the locations indicated by the fictitious dipoles when the photospheric field is very simple. They are found to be active regions.

Saito, T.↗

NASA NTRS1990

Disturbances of three cometary magnetospheres as explained by an MHD simulation

Outstanding disturbances of the plasma tails were observed in 1989 in three comets, Brorsen-Metcalf, Okazaki-Levy-Rudenko, and Aarseth-Brewington. Time variations of the tails were obtained from photographs provided by many astronomers. A 2-D MHD simulation was performed varying the speed and the direction of the solar wind flow. The simulation agreed quite well with the observations. Solar flares were identified as the sources of these disturbances. It was found that the sudden change in direction of the plasma tail axis occurs when the comet crosses a discontinuity surface of the solar wind structure accompanied by solar flares.

Kozuka, Y.↗