S. Christe [1], Sam Krucker [1], H. Hudson [1], R. Lin [1]
1 Space Sciences Lab, U.C. Berkeley
Presented at AAS/SPD 2009 (link)
Abstract
We present the first in-depth statistical survey of flare source heights observed by RHESSI between March 2002 and March 2007, a total of 25,705 events. These flares were found using a new flare-finding algorithm designed to search the 6-12 keV count-rate when RHESSI’s full sensitivity was available in order to find the smallest events. Thermal (4-10 keV) and nonthermal (15-25 keV) images were made for all microflares and source centroid locations were found for each event. In order to extract the height information from source positions, a Monte-Carlo model was developed with an assumed source height distribution where height is measured from the photosphere. We find that the best source height model is given by an exponential distribution with a scale height of 2.1 (0.3) Mm and a minimum height of 3.1 (0.3) Mm. Comparing with previously published loop length measurements, we find that the average loop tilt is ~44 degrees as measured from the vertical.
from www.smbc-comics.com.
Phillip Petit, in 1974, walked across the gap between the world trade center towers on a steel cable. Recently watched the very interesting documentary about it, Man on Wire. Apparently the name of the movie refers to the phrase that the NYPD used to described the “incident” in their police report when they arrested him, hilarious!
The Hinode broadband filter imager filters are as follows (fwhm);
- 3883.5 (7) Å CN I
- 3968.5 (3) Å Ca II H
- 4305.0 (8) Å blue continuum
- 5550.5 (4) Å green continuum
- 6684.4 (4) Å red continuum
- 4306.4 (6.3) Å G band
The resolution (keV) of the FOXSI DSSD as a function of temperature
Looming conferences bring such a keen focus to the mind.
Finally updated to a new version of wordpress! Can now updated from my iPhone (which is what I’m doing now). Hoping this will encourage me to update more…knock on wood.
Steven Christe, S. Krucker
Space Sciences Lab, U.C. Berkeley
Presented at Fall AGU Meeting 2008 (presentation link)
Abstract:
We present an in-depth statistical survey of flare heights of all X-ray microflares as observed by RHESSI between March 2002 and March 2007, a total of >25,000 events, an order of magnitude larger then previous studies. The microflares were found using a new flare-finding algorithm designed to search the 6– 12~keV count-rate when RHESSI’s full sensitivity was available in order to find the smallest events. The flare centroid position are found at the peak time and as a function of energy (3-6, 6-12, 12-25 keV). Flares are found to occur only in active regions, not in the “quiet” Sun. Flare heights are found using two independent methods including that of Matsushita (1992). The distribution of flares at the limb are fitted with a Monte Carlo simulations and the flare height deduced. We find that the 6-12 keV flare heights are consistent with a flare height of ~3 arcseconds above the photosphere with small separation between the thermal and nonthermal sources. The Matsushita method confirm these values.
Abstract Reference Number: 2516
Abstract Title: The Microflare Height Distribution
Paper Number: SH13A-1510
Presentation Type – POSTER
Cite abstracts as S. Christe and S. Krucker (2008), “The Microflare Height Distribution”, Eos Trans. AGU, 89(53), Fall Meet. Suppl., Abstract SH13A-1510
A meeting during from 8-12 December 2008 in Napa Valley. The webpage can be found here. Registration final deadline is November 10, 2008 (Monday). The full registration fee is $350. Earlybird registration ends soon on October 27, 2008 (Monday). The reduced registration fee is then $300. Registration fee for students is $125.
RHESSI Workshop Abstract
The Microflare Height Distribution
Christe, Steven; Krucker, Sam
We present an in-depth statistical survey of flare heights of all X-ray microflares as observed by RHESSI between March 2002 and March 2007, a total of >25,000 events, an order of magnitude larger then previous studies. The microflares were found using a new flare-finding algorithm designed to search the 6–12 keV count-rate when RHESSI’s full sensitivity was available in order to find the smallest events. The flare centroid position are found at the peak time and as a function of energy (3-6, 6-12, 12-25 keV). Flares are found to occur only in active regions, not in the “quiet” Sun. Flare heights are found using two independent methods including that of Matsushita (1992). The distribution of flares at the limb are fitted with a Monte Carlo simulations and the flare height deduced. We find that the 6-12 keV flare heights are consistent with a flare height of ~3 arcseconds above the photosphere with small separation between the thermal and nonthermal sources. The Matsushita method confirm these values….
