HINODE OBSERVATION OF THE MAGNETIC FIELDS IN A SUNSPOT LIGHT BRIDGE ACCOMPANIED BY LONG-LASTING CHROMOSPHERIC PLASMA EJECTIONS
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229-8510 (Japan)
- National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)
- High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States)
- Kwasan and Hida Observatories, Kyoto University, Kamitakara-cho, Takayama, Gifu 506-1314 (Japan)
We present high-resolution magnetic field measurements of a sunspot light bridge (LB) that produced chromospheric plasma ejections intermittently and recurrently for more than 1 day. The observations were carried out with the Hinode Solar Optical Telescope on 2007 April 29 and 30. The spectro-polarimeter reveals obliquely oriented magnetic fields with vertical electric current density higher than 100 mA m{sup -2} along the LB. The observations suggest that current-carrying highly twisted magnetic flux tubes are trapped below a cusp-shaped magnetic structure along the LB. The presence of trapped current-carrying flux tubes is essential for causing long-lasting chromospheric plasma ejections at the interface with pre-existing vertically oriented umbral fields. A bidirectional jet was clearly detected, suggesting magnetic reconnections occurring at very low altitudes, slightly above the height where the vector magnetic fields are measured. Moreover, we found another strong vertical electric current on the interface between the current-carrying flux tube and pre-existing umbral field, which might be a direct detection of the currents flowing in the current sheet formed at the magnetic reconnection sites.
- OSTI ID:
- 21300732
- Journal Information:
- Astrophysical Journal (Online), Vol. 696, Issue 1; Other Information: DOI: 10.1088/0004-637X/696/1/L66; Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-4357
- Country of Publication:
- United States
- Language:
- English
Similar Records
ON THE FORCE-FREE NATURE OF PHOTOSPHERIC SUNSPOT MAGNETIC FIELDS AS OBSERVED FROM HINODE (SOT/SP)
STATISTICAL STUDY OF CHROMOSPHERIC ANEMONE JETS OBSERVED WITH HINODE/SOT