qs085.nakakubo01 Posted: 26-Jan-95 Updated: 3-Sep-95, 7-May-96 Events specified: N/A
Kayoko Nakakubo, Hirohisa Hara, Takeo Kosugi
A new observational discovery called 'the extended activity cycle' was recently made by Wilson et al. (Nature, 1988), although Waldmeier and others who observed the corona with coronagraphs had noticed the existence more than 20 years ago. We will look for the activity with Yohkoh SXT data, and look into the behavior of the corona in detail. We will make a data base from the Yohkoh data to study this subject.
The data base consists of the data of soft X-ray intensity against the position angle at a certain height, for example, r=1.15*Rs (Rs: solar radius). We investigate the migration of the structure at the high-latitude.
This is a study for an undergraduate student (Kayoko Nakakubo). And this is a work related to the topic of qs053.hara04.
Update 7-May-96
I'll send a progress report for our research work
Title: High Latitude Activity Zones in the Solar Corona Collabolators: Kayoko Nakakubo, Hirohisa Hara, Takeo Kosugi
We study about the structure corresponding to the High Latitude Activity Zones (HLAZs). We confirm that the High Latitude Activity is also observed in the Yohkoh SXT da ta. And the coronal structures corresponding to the HLAZs are identified in the original soft X-ray images, they are classified into four types:
type I ... Arcade-loop type expanding with time.
type II ... Small Arcade-loop type whose shape changes little.
type III... Arcade-loop type.
Both of its foot-points exist in Main Activity Zone.
In other words, this loop originates in the Main Activity Zone
and is seem in high latitudes.
type IV... Non-loop type.
In these types, type I is most frequently observed, namely, in 16 cases out of 2 3.
Update 3-Sep-95
any people who observed the corona with coronagraphs had noticed the existence of the High Latitude Activity Zones (HLAZs). But a structure corresponding to the HLAZs has not been identified yet.
We use Yohkoh soft X-ray images to identify the structure of the HLAZs. We extract soft X-ray intensities annually at a certain height above the limb as a function of the position angle from Yohkoh soft X-ray images, and confirm that the HLAZs are also observed in the Yohkoh SXT data.
We identify structures of the HLAZs in the original soft X-ray images. At present we look into 23 samples of the structure and classify these into four types. We intend to look into the structures more carefully.