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Transcript of Natalie presentation3
Modeling Solar Flares Using Tapered Coronal Loops
Natalie Larson Dr. Kathy Reeves, Dr. Trae Winter
Harvard Smithsonian Center for Astrophysics Solar Physics REU 2010
What is a solar flare?Rapid, intense brightening in X-ray emissions
TRACE XRT
Closer view of solar flare
• Magnetic field lines of two fields are joined, creating a new magnetic field configuration http://cse.ssl.berkeley.edu/segwayed/lessons/exploring_magnetism/in_Solar_Flares/s4.html
The project: this summer
• Modeling a flare with tapered loops causes:• More accurate representation of flare loop• Energy and density variations along the loop• Non-thermal particle mirroring
Method•Generate flare using Kathy’s model
•Get Energy and Geometry•Put Energy and Geometry into Natalie’s Heating Function
•Trae’s model works with Natalie’s heating function to describe evolution of temperature and density in flare
The project: long-term goals
Understand relationship between energy release and hard and soft X-rays
Amount of energy input that produces particular hard and soft X-ray light curves by varying energy input into model
Conditions under which Neupert Effect is seen
Relationship between peak soft X-ray flux and total energy input
Kathy’s Model
• Loss-of-equilibrium model
• Input: Original magnetic configuration, input energy
• Output: energy released and geometry of the loop
Reeves, Warren, and Forbes, 2007
Kathy’s Model
• Output agrees well with observed flaresLin et. al., ApJ, 2005
Trae’s Model: HyLoop
• HyLoop: The controller.
• SHReC: Solar Hydrodynamic Equation Codes (thermal particles)
• PATC: Particle Tracking Codes (non-thermal particles)
My contribution
• Heating function
• Kathy’s code->Heating function<->Trae’s code• Uses Gaussian function to distribute energy over loop length• Uses triangle function for energy in the loop over time
• GOES flux simulation: • Input: temperature and emission measure at each second• -> GOES module calculates flux (Watts/m^2)• Output: Sum of all flux in the flare at each second
• Light curves, plots, analysis
• Miscellaneous intermediate plots and validity-checking
Results: GOES light curves
Results: temperature and density
Results: XRT light curves
Future Work• Compare previous and new values for peak soft X-ray
flux in flare to total energy input in flare (need to model more than one flare to do this)
• Vary energy input in flare to find light curve that best fits observations to approximate real energy input in flare
• Model entire flare in hard X-rays and compare light curve to derivative of the soft X-ray light curve (Neupert Effect)
• Compare simulated and observed soft and hard X-ray light curves and (simulated) input energy (need to model all loops with NT particles, and need to model more than one flare)
Thank you!
• Kathy and Trae!
• CfA: Solar Group
• NSF
References
Evolution of Temperature and Pressure