Climate change, and sustainable food & energy production:
With expertise in energy physics, modeling of nonlinear dynamic systems, and organic farming, Zita is shifting her research to sustainability & climate change Many students have done fine projects on sustainable energy & food production in her academic programs. Zita is working with Scott Morgan and Judy Cushing to establish a new long-term research programme at Evergreen. With Judy and Dominique Bachelet, we will model land use impacts on climate change. With Scott, we will plan and facilitate sustainability projects on campus. Students interested in sustainability and climate chang, with strong potential in agriculture, science, math, computing, engineering, architecture, building, design, etc., are encouraged to join us in the Energy Systems & Climate Change program in 2013-14, and/or research contracts in summer 2014.
Students interested in sustainable agriculture and land use may also learn from experience on the Armstrong-Zita Ranch in the Tumwater urban growth area, less than 15 minutes from campus. This 15 acre organic farm produces grass-fed beef and pastured poultry, while preserving and improving an historic farm. Learning contracts on the farm may be available in any season. Farm research projects may be designed in consultation with students, e.g. in poultry/garden co-management, pasture and forest management, soil quality studies, pasture rotation, solar charged fencing, irrigation, fodder production, gardening, composting, and more. Local sustainable food production is informed by our committee work with the Thurston County Ag Advisory Board and the Thurston Food System Council.
Stellar magnetohydrodynamics, esp. solar physics:
Acknowledgements: Work since 2001 (on chromospheric waves) was supported by the National Science Foundation under Grant No. 9806188, Grant No. 9414037, and/or NASA's Sun-Earth Connection Guest Investigator Program, NRA 00-OSS-01 SEC.
Solar dynamo research since 2004 was partially supported supported by NASA grants NNH05AB521, NNH06AD51I and the NCAR Director's opportunity fund; NSF grant 0807651, the Visitor Program of the High Altitude Observatory at NCAR, and The Evergreeen State College's Sponsored Research program.
The National Center for Atmospheric Research (NCAR) is sponsored by the National Science Foundation (NSF).
Our research since 2008 is supported by NSF grant No. 0807651.
findings, and conclusions or recommendations expressed in this material are
those of the author(s) and do not necessarily reflect the views of the NSF, NASA, or host institutions.
Evergreen's summer research
in solar physics
Working at LMSAL: manuals by Nina Smith and Chris Ballou (to be uploaded soon)
2010: Three Evergreen students worked at LMSAL again this summer. Nina Smith developed tools and analyzed surface flows in the presence of tilted magnetic fields (1), Chris Ballou developed tools and analyzed waves in active regions (2), and Benji Friedman made movies of solar dynamics for publication online (3). Zita finished her dynamo paper and generated data with Neal Hurlburt's MHD code to illustrate advection of magnetic fields due to diffusivity gradients (4). Special thanks to (1) Dick Shine and Mark DeRosa, (2) Mark Cheung, (3) Zoe Frank, and (4) Chris Heck for their generous help.
Check back here for links to our recent work, to be presented at the APS-NW conference in Oct. 2010.
|2009: Three Evergreen students (Clay Showalter, Riley Rex, and Ian Ruotsala) learned to analyse solar atmospheric data with Dr. Neal Hurlburt at LMSAL in Palo Alto. They wrote game/tutorial software to enable many others to contribute to analysis of data from SDO and other solar observatories.
Zita modified her dynamo paper and finished analytic work deriving magnetic advection from diffusivity gradients.
|2006-8: Zita did solar dynamo work in Boulder with Dr. Mausumi Dikpati (and Peter Gilman) in Boulder. Our paper was submitted for publication.|
Summer 2004: Night Song worked on solar
dynamo simulations, with Dr. Mausumi Dikpati and Eric McDonald, and
Summer 2002: Noah Heller analyzed data from a satellite observing the Sun, with Dr. Phil Judge
|Summer 2001: Matt Johnson and Sara Petty-Powell analyzed simulations of magnetic waves in the Sun's atmosphere, with Dr. Tom Bogdan.|
|Plasmas and magnetohydrodnamics
Plasma is hot ionized gas. Heat a solid, and it melts to liquid. Heat a liquid, and it vaporizes to gas. Heat a gas, and it ionizes to plasma. While plasma is blood to biologists, it is something completely different but just as vital to physicists. Plasma, a neutral fluid of charged particles, comprises most of the visible universe. The Sun and every shining star is made of plasma. Galaxies are made of stars, and the spaces between stars are filled with thin hot gas. The glowing red aurora in the photo above is from plasma: charged particles stream from the Sun, become trapped in Earth's magnetic field, and excite gases in our upper atmosphere. We are interested in how plasmas interact with - and create - magnetic fields.Papers and presentations by E.J. Zita and *Evergreen students
Worksheets on Solar Magnetohydrodynamics - students work these and other derivations with Zita to prepare for summer research. (Thanks to Sara for formatting these.)
Colleagues and links
|Magnetic fields heat the Sun:
The sun is hot deep inside and much cooler on the surface. You would expect the solar atmosphere to get cooler the higher up you go, but the Sun's atmosphere is surprisingly hot. Researchers are pretty sure that magnetic processes heat the solar atmosphere, but we are not sure exactly how. This is where you come in.
News, March 2001: Dr. E.J. Zita of The Evergreen State College and Dr. Thomas Bogdan of the High Altitude Observatory (HAO) at the National Center for Atmospheric Research in Boulder have been awarded a 3-year research grant by NASA. This $225,5000 grant will support their research into the role of magnetic fields in heating the atmosphere of the Sun. Zita and Bogdan began their work together in Spring 2000, when Zita's expiring National Science Foundation (NSF) grant funded one quarter of unpaid leave from Evergreen. Their continuing analytic work on the effect of magnetic shear on plasma dynamics will be combined with numerical calculations on heating processes in the Sun, and compared with extensive datasets from solar observatories and satellites. The NASA grant provides for Evergreen students to contribute to new computations and data analysis, on campus and in visits to HAO, in collaboration with colleagues from Boulder, Oslo, and London. This new work builds on Zita's past efforts to expand opportunities for Evergreen students interested in astronomy and astrophysics, including access to the UW's Manastash Ridge Observatory and construction of a modest on-campus observatory for the College's Meade LX-200 telescope, funded by the NSF. Zita continues to welcome new students to her research team, many of whom start by taking her spring Astronomy and Cosmologies program.
Summer 2001: Matt Johnson and Sara Petty-Powell spent July in Boulder working with Zita and Bogdan, and August at Evergreen continuing their work. They analyzed data from Rosenthal and Nordlund's 3D MHD code, calculated energy flux near a vertically oscillating sunspot, and found that energy oscillates between magnetic compression and magnetic bending as MHD waves rise from the photosphere. As photospheric sound waves rise, they transform into shocks and Alfvenic and magnetosonic waves, which may contribute to heating. Zita got the sheared-field wave equations into a tractable form by transforming everying to the sheared frame. We all presented our work at the Institute for Theoretical Physics in Santa Barbara in Jan 2001.
Summer 2002: Noah Heller and Zita worked with Phil Judge at HOA and Evergreen. We analyzed chromospheric UV oscillation data from SUMER and found that sound waves (2-5 mHz) do lose power as they rise above the photosphere, as inferred from our simulation analyses last year. Lower frequency oscillations (0-2 mHz) are stronger in magnetic (network) regions of the chromosphere, and higher frequency oscillations (5-10 mHz) are stronger in internetwork regions. Zita found solutions to a special case of the wave equations in a sheared magnetic field. We presented these results at the SHINE meeting in Banff in Aug.2002.
|Many stars ring with sound waves,
whether they are magnetic or not. We can see the sound waves, but
we can't hear them because (1) their frequencies are not in the audible
range and (2) sound doesn't travel in the vacuum of space. Sound
waves in a star are basically compressions and expansions of the
stellar material, a hot ionized gas called plasma. The sound waves
are oscillations trapped between the star's surface, where they are reflected
(since they cannot propagate in space), and the star's inner regions, where
the denser plasma refracts sound waves back toward the surface.
Astronomers can tell stars are ringing when their brightness varies in characteristic ways. We know why the Sun rings: convection cells make the photosphere oscillate. We know why delta-Scuti stars ring: opaque regions of the star block the outflow of radiation, exciting convection. But we don't know why rapidly oscillating peculiar A (roAp) stars ring. The usual explanations (convection or opacity mechanisms) don't seem to work in roAp stars. Astronomers are pretty sure that roAp sound waves are somehow connected with the stars' strong magnetic fields, because they have the same spatial symmetry, and because Ap stars don't ring unless they have a strong magnetic field. But how, exactly, do the stars' magnetic fields affect their sound waves?
Zita has an idea about how the magnetic fields of roAp stars could cause their sound waves. The twisted magnetic fields have an equilibrium shape, or minimum energy configuration. At rest, the magnetic field would maintain its shape, rather like a slinky toy distorted into a spherical shape. If you stretch and release a slinky toy, it oscillates near its minimum energy state. Similarly, the magnetic fields in roAp stars can twist and untwist near their equilibrium shape. These magnetic oscillations induce new electromagnetic fields, and the fields interact to drive magnetoacoustic modes, or magnetic sound waves, in the edge of the star. The oscillating surface of the star makes it brighten and dim in a periodic way.
Does this idea work? It looks good, but we'd like to be sure. Initial calculations of Zita's magnetoacoustic modes are consistent with the sound waves observed in roAp stars. They oscillate with periods of several minutes, or frequencies of a few milliseconds. There is more than enough magnetic energy available to power the motion of the stellar plasma. And the magnetic wavelengths are consistent with the observed size of the sound waves. Zita's model can be tested by comparing observations with her predictions. How do the sound waves change in bigger stars, or more magnetic stars? The model predicts that bigger (or more strongly magnetic) stars will pulse slightly more slowly. The first Canadian space telescope, the MOST, will be able to test these predictions in 2002.
Students generated predictions from Zita's model so it can be compared to observations of individual stars. Tomoko Adachi and Karen O'Meara computed hydrostatic equilibria of stars (using Steve Kawaler's easy-to-run ZAMSprogram in the CAL), then calculated the frequency of magnetosonic modes in the stars using Excel. Karen also used Mathematica to help Zita solve wave equations for how magnetosonic frequencies change with complicated magnetic fields. Christopher used Mathematica and some of his own C++ programs to visualize what the twisted magnetic fields look like inside the stars, and how they twist and untwist when they oscillate. Lovely! Claire Rosen, Michael Martin, and Jenny Pegg have begun a little work in this area too.
Meanwhile, other students learned to make research-quiality observations of stars. For example, in summer 1999, Andrea Nowicki and Sara Petty-Powell operated UW's 0.8 m telescope at Manastash Ridge Observatory (MRO), to take digital images of stars, and to analyze the data using IRAF, a standard package of professional astronomy software. Our colleague, Dr. Paula Szkody has since set up MRO to make remote observations for distant users like Evergreen students.
Our calculations and observations continue. One
product of Zita's model of magnetic oscillations in roAp stars is a new
dynamo model that might explain how some hot stars can sustain their magnetic
fields without convection. We would like to see whether this turbulent
dynamo can explain new observations of magnetic fields in B stars.
This may require running 3D magnetohydrodynamics calculations on a supercomputer.
Any student interested in carrying out any part of these investigations
is encouraged to contact Zita with a research proposal.
Please contact Zita by email for details (zita(at)evergreen.edu) and put "RESEARCH" in the subject header.
|Tom Bogdan, B.C. Low, Phil Judge
High Altitude Observatory (HAO), National Center for Atmospheric Research (NCAR), Solar Atmosphere and Heliosphere (SAH) group
|animations of stars, by ISU||Fusion energy research at General Atomic: D III D||LaTex on Linux info|
by Mats Carlsson, Institute for
Theoretical Astrophysics, University
of Oslo, Norway
Colin Rosenthal and Ake Nordlund on MHD waves and p modes
|Iowa State University Astronomy and Physics and the Whole Earth Telescope||University of Wisconsin-Madison Plasma Physics||Los Alamos unrefereed e-print archives|
|Helicity by Mitch Berger||Washington State University Astronomyand Physics||Los Alamos: fusion||Basic Facts about magnetic fields in space (Michigan)|
|Helioseismology by Jørgen Christensen-Dalsgaard||SOHO
Heleioseismology by VIRGO
|Fusion news from Division of Plasmas Physics||Fusion advisory committee interim report, Aug. 99|
|Geodynamo by Gary Glatzmaier||Los Alamos Stellar Pulsation discussions|
|animations of stars, by Guenther||new telescopes for pulsating stars: MOST (Canada) and MONS (Denmark|
|Rattlesnake Mountain Observatory and AASTA||Pacific Northwest National Lab|
|University of Washington-Seattle Astronomy
Ridge Observatory (schedule)
MRO school outreach program
|University of Washington-Seattle Geophysics and Plasma Physics|
|AAVSO and Project ASTRO|
Perkins, S. (2001, Jan. 20) Pinning down the sun-climate connection. Science News, 159, 3. Retrieved on May 11, 2005, from http://www.sciencenews.org/articles/20010120/bob10.asp
Reid, G. C. (1995). The sun-climate question: Is there a real connection? Reviews of Geophysics, Vol. 33 Supplement. Retrieved on May 7, 2005, from http://www.agu.org/revgeophys/reid00/reid00.html
Rind, D. (2002, April 26). The suns role in climate variations. Science, 296, 673-677. Retrieved May 10, 2005, from http://solar-center.stanford.edu/sun-earth/sun-climate.science020426.pdf
Perkins, Reid, Rind references thanks to Bryan Johns and Rob Whitlock, Sunspotters research project in Astronomy & Cosmologies, spring 2005
Acknowledgements: thanks to
Bill Titus, Rich Noer, Carleton College faculty
Rob LaHaye, Mike Shaffer, Gary Jackson, Tony Taylor, and the OHTE and D-III-D teams at General Atomic
Carter Munson, Ken Schoenberg, and the ZT-40 team at Los Alamos
Stewart Prager, University of Wisconsin, Madison, graduate advisor
Dalton Schnack and Bill Ho, SAIC
Steve Kawaler, Iowa State University, Ames, for the introduction to roAp stars
Eric Leber, PPNL and Rattlesnake Mountain Observatory, and Carl Pennypacker, LBL and HOU
Katy Garmany and Irene, UC Boulder, for teaching physicists how to teach astronomy
Paula Szkody and colleagues, University of Washington, Seattle, for teaching us to use Manastash Ridge Observatory
Don Middendorf and Rob Knapp, The Evergreen State College
George Michel, Robyn Herring, and Nancy Johns, and Enrique Riveros-Schaffer,, TESC, for observatory planning and permitting support
B.C. Low, Tom Bogdan, and the HAO team at NCAR
hardworking students who ask good questions
The National Science Foundation (NSF) for funding 1995-2000 research
The Evergreen State College (TESC), for Sponsored Research support
NASA for funding 2001-2003 research