5 research outputs found
Comparative Analysis of a Transition Region Bright Point with a Blinker and Coronal Bright Point Using Multiple EIS Emission Lines
Since their discovery twenty year ago, transition region bright points
(TRBPs) have never been observed spectroscopically. Bright point properties
have not been compared with similar transition region and coronal structures.
In this work we have investigated three transient quiet Sun brightenings
including a TRBP, a coronal BP (CBP) and a blinker. We use time-series
observations of the extreme ultraviolet emission lines of a wide range of
temperature T (log T = 5.3 - 6.4) from the EUV imaging spectrometer (EIS)
onboard the Hinode satellite. We present the EIS temperature maps and Doppler
maps, which are compared with magnetograms from the Michelson Doppler Imager
(MDI) onboard the SOHO satellite. Doppler velocities of the TR BP and blinker
are <,25 km s, which is typical of transient TR phenomena. The Dopper
velocities of the CBP were found to be < 20 km s^{-1} with exception of those
measured at log T = 6.2 where a distinct bi-directional jet is observed. From
an EM loci analysis we find evidence of single and double isothermal components
in the TRBP and CBP, respectively. TRBP and CBP loci curves are characterized
by broad distributions suggesting the existence of unresolved structure. By
comparing and contrasting the physical characteristics of the events we find
the BP phenomena are an indication of multi-scaled self similarity, given
similarities in both their underlying magnetic field configuration and
evolution in relation to EUV flux changes. In contrast, the blinker phenomena
and the TRBP are sufficiently dissimilar in their observed properties as to
constitute different event classes. Our work indicates that the measurement of
similar characteristics across multiple event types holds class-predictive
power, and is a significant step towards automated solar atmospheric
multi-class classification of unresolved transient EUV sources.Comment: 38 pages, 16 figure