| Thursday 23
July Today I added the trajectories of the centroids to my movie. The results are shown here. The trajectories suggest that the centroids follow the path of an archimedian spiral. Wednesday, 22 July I managed to project the magnetogram unto the tangent plane only to discover I only needed to transform two vectors: that joining the two centroids and that on the inversion line. The idea is to calculate and study the angle between those two vectors. Given that my algorithm for calculating the inversion line has some problems and sometimes fails me here is cleaned up version of the angle versus the frame number. angle versus frame number Thursday, 16 July I spent the day miserably trying to work out how to find the projection of an active region in the line of sight on its tangent plane. I don't fully understand how to do it. I'll ask Dana about it tomorrow. Tuesday, 14 July Bastille day today! And it was indeed a good day. I added the line tangent to the inversion-line at its intersection with that connecting the two centroids. Another frustrating affair involving creating my own contour plot and finding the point of intersection. Friday, 10 July I DID IT! After a week of hair-pulling debugging, these active regions are finally centred! Tuesday, 7 July Utter frustration! I can't make this movie work! It's been two days and I seem to have made a mess out of my program. Wednesday, 1 July The last two days have been spent fixing some idl issues on my plots, which after consulting Dana appear to have been non-existent. Anyway I now have a new substantial idl assignment: centre the active regions in the movie. Friday, 26 June I never thought plotting graphs would take that long but idl keeps complaining about everything. I might also be trying to make things too complicated. Dana seems to be most interested in the ones whose centroid rotate around its centre: Plots of rotating active regions. These active regions display a linear relationship between the angle of rotation and the distance between the 2 centroids akin to an Archimedian spiral. We are definitely starting to focus more on helicity from now on it seems. Monday, 22 June The trimming is finally completed and I am now left with a healthy set of active regions to work with, about 40 or so. Thus half were either too small to be of interest or they were so butchered that keeping them was just a waste of memory space. I am now looking to extricate some sort of relationship between various parameters. To start with I have to graph angle between the horizontal axis and the line joining the two centroids versus the magnetic flux, the angle versus the distance between the two centroids and the magnetic flux versus the distance. Unfortunately given that I haven't been programming recently my progress is enervingly slow for such an easy task. I am trying to plot those graphs for all active regions on the same page. Thrusday , 18 June One of Dana's program called bp_emerge, which process all the frames and stores the data in a .pns file, is giving me trouble. It is refusing to cooperate when the magnetic flux of either polarity is too small. Given that I had made a point of tracking the active regions from early emergence I need to trim down most of them and that is an excruciatingly long and tiresome process. Wednesday, 17 June It's done! Finally all the active regions that are isolated and big enough have been all tracked down. I now have at least 70 of them stored in my data file. Dana still isn't back but that leaves me the opportunity to play around with them and get accostumed to his programs. Friday, 12 June I spent the entire last three days manually drawing circles around active regions using one of Dana's programs called emerge_track. That program simply tracks a designated AR for about 50 to 70 frames and requires the user to encircle a region for each. The entire region is masked, leaving only the selected area with non-zero magnetic flux for further analysis. That work is rather laborious as there are at least 200 potential active regions in the last 10 years. Tuesday, 8 June I spent the morning collecting data. After that I scanned a few of Dana's programs for internal IDL commands and other idiocincracies. I just want to make sure I know IDL well by the time the project shifts into data analysis mode. Monday, 8 June Today was mostly spent reviewing Friday's notes taken during the meeting and collecting data. Dana is leaving Wednesday so the next few days will be spent capturing the formation of active regions from magnetograms collected from 1996. The most isolated ones I found where during solar minimum, which makes sense because the lack of magnetic activity diminishes the chance of entanglement. Friday, 5 June I had a 5 minute presentation of my idl project to the REU group and a couple of mentors. Fairly relaxed affair, I must say. I then read up on some statistics that could prove useful for my project and meet Dana Longcope for 2 hours. He showed me how to track active regions from magnetograms and how to analyze them using the various programs he wrote. I was in serious need of aspirin after that meeting... Anyway the next 2 weeks or so will be spent gathering data of active regions. Thrusday, 4 June My supervisor, Prof. Dana Longcope, has been away but is now expected to return some time today. His absence gives me a bit more time to polish my programming skills with a project given yesterday. It consists of analyzing a magnetogram using various pre-written programs. The idea is to (1) focus on an active region, (2) filter the regions of insignificant magnetic activity leaving only regions of significant magnetic activity and (3) simplify the topography of these sources to poles of varying magnetic intensity for further analysis. All of the code was already written so my job was to fiddle around with the poles. For instance I found the centroid for each polarity, the average distance between the pole with the greatest flux and the poles of opposite polarity and other niceties. Even though the programs I wrote were fairly simple I definitely needed a gentle refresher in the dark arts of idl programming. Dana is finally back. Met with him for 30 minutes or so to discuss our project. Nothing really constructive really came out of the meeting but some interesting ideas were thrown around and could potentially be explored. One involves some statistical analysis and that would require a serious amount of revision for I don't remember much of my statistics classes. Could be fun though. Tuesday, 2 June Today second idl session followed by a html practical. Good stuff! All these sessions are
rather
basic but I need a project to sharpen my teeth on, which I'll be
getting tomorrow. Later in the afternoon I tried to read the various
publications Dana sent me but the stuff left me slightly puzzled.
Something to do with magnetic helicity. As usual those articles will
become obvious once I get an oral explanation but I'll give a better
shot at them tonight.
|