Analysis of the Temperature and Emission Measure of Solar Coronal Arcades and Test of Flare/Arcade Loop Length ( Yamamoto, Shiota, Sakajiri, Akiyama, Isobe, and Shibata ) Presented By H.D. Winter

Outline I.Why I chose this paper II.Background needed to understand paper III.Purpose of Paper IV.What they said V.Obvious problems with Paper VI.Implications of Paper

Why I chose this paper Directly parallels the work being done in PHYS 580 (HD/MHD class) Current research work is focusing on numerical modeling of flaring loops SXT observation are used in determining relevance of the Emission Measure to Temperature scaling “law” Implications for SADE

Background I Work began as a result of an observational paper by Feldman, Laming, and Doschek (1995) that combined SXT flare observations with the observations of extra-solar flares observed by the Ginga satellite.

Background II Using several assumed boundary conditions the group states that the relationship between temperature and emission measure scales as Using an energy balance between conductive cooling and Petschek reconnection heating And a balance between gas and magnetic pressure

Purpose of the Paper The purpose of this paper was to test the modeling predictions of previous works with physical observables (i.e. loop length and temperature) Examine a correlation between flare heating mechanism and arcade heating mechanisms Elimination of possible heating mechanisms by using the Emission Measure/ Temperature Power law index=17/2 (Shibata & Yokoyama, 1999) 1.Joule heating Index =13/4 NO! 2.Parker nanoflare heating EM is 9 orders of magnitude lower than what is observed in the corona WHAT!!! 3.Alfvén wave heating EM is 13 orders of magnitude larger than the observed value if the velocity amplitude of the Alfven waves is WHAT!!!

What they said. I Assuming constant Loop width a result from previous work is given (Yokoyama & Shibata, 1998), and a β=0.2 gives Equation 6

What they said. II Compare L theory to L obs for 17 arcades for which temperature and emission measure can be determined and for 64 flares observed in SXT and HXT and you get

Obvious Problems of the Paper ASSUMPTIONS!!! How can anything be constant in flares and arcades! Normalization of Equation 3 Use of 2-D modeling Same heating function for arcade and flare?? Data selection Bias? EM estimates for other heating mechanisms

1.Joule heating Index =13/4 NO! 2.Parker nanoflare heating EM is 9 orders of magnitude lower than what is observed in the corona WHAT!!! 3.Alfvén wave heating EM is 13 orders of magnitude larger than the observed value if the velocity amplitude of the Alfven waves is WHAT!!!

Implications of Paper For flares if you know T you know EM Law can be restated for different values of

Implications of Paper II