Monday, July 20, 2015

Someone you should know: Lauren Woolsey, cont.

Lauren Woolsey received her Bachelor's Degree at the University of Maryland, College Park.  While there, she proactively found opportunities that would satisfy her passion for astronomy.  One of these opportunities included an internship at the Goddard Space Flight Center (GSFC).  Conveniently, the GSFC is not far away from the university.  Lauren earned an internship there both her sophomore and senior year of college.  During these undergraduate years she was also occupied with her job as a Teaching Assistant during her junior year.  After that year, she landed an internship under the NSF-funded Solar REU program at the Harvard-Smithsonian Center for Astrophysics (CfA).

These accomplishments are but a few of many reasons why she was a strong applicant when applying for graduate schools during her senior year.  Consequently, she was accepted into the Astronomy Department of Harvard's Graduate School of Arts and Sciences.  Since then, she has been working with Steve Cranmer on modeling the influence of different magnetic field geometries on the solar wind.

When I spoke to Lauren about her professional background, I was intrigued by the diversity of her undergraduate research experiences.  At Goddard, she studied planetary surfaces and specifically analyzed topographical maps of Mars and the Moon to see how the rate of crater formation and history of impacts have affected certain locations.  At her undergraduate internship at the CfA, her project involved comparing and contrasting a solar wind model to observations recorded by the SOHO Ultraviolet Coronagraph Spectrometer.  At the end of her senior year, she finished her Honors thesis project in which she sought to explain the tilt of Uranus via a non-linear resonance in the different orbital and inclination frequencies of the solar system.

Now that she is a Ph.D. candidate, her research experiences are only getting more interesting.  For most of her graduate career as Steve Cranmer’s advisee, she has been modeling how magnetic fields affect solar wind.  One parameter that has been of interest to her is the magnetic field ratio between the photosphere and a region called the source surface. The source surface surrounds the Sun at a distance of 2.5 solar radii from the solar core.

Lauren is one of many astronomers who focus on the theory behind a phenomenon more than current data gathered via observations.  As a theorist, she has been working with models that attempt to imitate solar wind speed that has been observed in reality.  The field ratio has proven to be useful for modeling this solar wind speed and thus it’s also been beneficial towards finding a better correlation between the Sun’s magnetic field and solar wind properties.  Furthermore, finding a better correlation might even lead scientists to better comprehending one of the most famously unsolved problems in the astronomy community: why is the outermost atmospheric layer of the Sun hotter than most regions closer to the Sun’s extremely hot core?

What makes this enigma even more flabbergasting is that scientists know specifically where this phenomenon is taking place and still have yet to figure out this problem.  The region where the temperature of the Sun drastically increases is called the transition region.  The transition region dwells immediately above the chromosphere and occupies a thin layer of the Sun’s corona.  The solution to this problem seems to be occurring in this transition region; however, scientists do not currently know why it is happening and what mechanism, starting in the transition region or below, is causing the temperature to be so high in the corona.

Lauren started her search for the relation between the magnetic field and solar wind properties by working with one-dimensional models. The model represented the magnetic field strength as a function of height.  The footpoint of the model acted as the photosphere while the source region was the source surface.

Figure 1: Plot of relationship between magnetic field strength and altitude.  The information comes from Lauren's one-dimensional modeling from photosphere to source surface.  The rightmost dashed line aligns with 1.50 on the x-axis, representing the source region (2.50 \(R_{\odot}\) away from Sun’s core).  For a more detailed explanation of this plot, see Lauren's paper.
After working with that model she took it a step further and considered additional information from a higher-dimensional code with time dependence.  With this model, astronomers are given a more clear understanding of how significantly the magnetic field ratio affects certain properties of the solar wind.  This newfound understanding is primarily due to how well the model replicates events on the Sun that have been observed in reality.

Figure 2: 3-dimensional model of magnetic field lines between footpoint (bottom of imaginary cylinder) and source region (top of cylinder).  According to the model, this is the configuration of the magnetic field lines at a specific moment in time. (van Ballegooijen et al. 2011)
Because modeling inevitably entails the comparison of the model to data measured in reality, Lauren’s most recent work involves data taken of network jets on the Sun.  Network jets are bright, short-lived, linear features in the chromosphere.

Figure 3: Observation of solar network jets present within the red dashed circle. (Picture Credit: NASA/IRIS)
Lauren is currently conducting research on these solar network jets and hopes that her newfound knowledge will ameliorate her previous work with modeling or simply prove how well the models work. In turn, she will be able to improve the current understanding of the physics behind the correlation between magnetic field strength and solar wind properties.  While working on this she has managed to publish a paper this past March.  She has also finished another paper recently which will soon be published.  It is obvious that she knows and enjoys the essence of writing and communicating her research to the scientific community.  She is a testament to the fact that writing is an essential part of a researcher’s life.  That form of communication is vital to the productivity and knowledge of the astronomy community.  I hope to see her work continue to benefit the astronomy community as well as lead to breakthroughs in science that would ameliorate the well-being of all of mankind.


You can learn more about Lauren at www.cfa.harvard.edu/~lwoolsey or follow her on Twitter @cgsunit.

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