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 change, 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.
- Group contracts with students who have done good work in one of Zita’s academic programs are strongly preferred over individual contracts.
- Contact firstname.lastname@example.org at least a month in advance
- with your research interest in the Subject Header, e.g. Farm Contract, Sustainable Energy Production Research, or Climate Change Modeling Research.
- Include concise specifics about your experience and studies in farming/gardening, equipment use, energy and climate change, math, science, computing, etc.
- List your recent programs at Evergreen, with faculty names. Attach your evaluations if possible.
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 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 Evergreen 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.
Any opinions, 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
Evergreen undergraduates have had opportunities to work with Zita and research colleagues at the High Altitude Observatory (HAO) at the National Center for Atmospheric Research (NCAR) in Boulder, CO and, most recently, at Lockheed Martin Solar and Astrophysics Laboratory in Palo Alto, associated with Stanford University. We are studying magnetic dynamics in the Sun. Our work contributes to efforts to answer questions such as:
How does this contribute to the magnetic storms Earth experiences when the Sun’s field reverses?
- How do dynamic interactions between material properties of the Sun and its magnetic field change each other and affect the solar dynamo?
- Can we predict short term details and long term patterns of the Sun’s magnetic reversals?
- What can we learn by analyzing data from the solar atmosphere?
- How can we productively handle the massive amounts of data from NASA and Lockheed’s new Solar Dynamics Observatory (SDO)?
- How can we help design software to make solar data analysis accessible to students everywhere and the general public?
Working at LMSAL: manuals by Nina Smith and Chris Ballou (to be uploaded soon)
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.
Three Evergreen students (Clay Showalter, Riley Rex, and Ian Ruotsala) learned to analyze 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.
Zita did solar dynamo work in Boulder with Dr. Mausumi Dikpati (and Peter Gilman) in Boulder. Our paper was submitted for publication.
Jada Maxwell studied solar magnetic waves sources for auroral infrasound, and Zita continued solar dynamo work with Mausumi and Eric.
(photo by Mark Urwiller)
Night Song worked on solar dynamo simulations, with Dr. Mausumi Dikpati and Eric McDonald, and
Chris Dove analyzed simulations of magnetic waves in the Sun’s atmosphere, with Dr. Tom Bogdan.
Noah Heller analyzed data from a satellite observing the Sun, with Dr. Phil Judge
Matt Johnson and Sara Petty-Powell analyzed simulations of magnetic waves in the Sun’s atmosphere, with Dr. Tom Bogdan.
Plasmas and magnetohydrodynamics: from fusion to astrophysics
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.
Plasma physicists investigate questions such as:
- Fusion: How can magnetic trapping help researchers build a sun in the lab, for safer, cleaner energy?
- Magnetic stars: Can magnetic dynamics help explain observed fluctuations in hot stars?
- Solar magnetism: Why does the Sun’s magnetic field flip every 11 years?
- Solar weather: Why is the Sun’s atmosphere millions of degrees hotter than the solar surface? How do magnetic waves help heat the Sun’s atmosphere?
- Space weather: How does solar radiation change, and how does it affect Earth?
All these investigations involve magnetohydrodynamics (MHD), the study of motions of magnetized fluids, especially plasmas. Mathematically, magnetohydrodynamics can be described with Maxwell’s equations (electromagnetic theory) and conservation laws (for mass, momentum, and energy). This coupled set of nonlinear differential equations can be solved exactly only in special cases (analytical MHD theory). In more complex, realistic cases, these equations can be solved approximately by supercomputers (MHD computation). We aim to compare analytical and computational results with physical data. Where they agree, we can learn new insights about how magnetic plasmas work.
Papers and presentations by E.J. Zita and *Evergreen students
Zita, E.J. & Dikpati, M., ”Sensitivity of a Babcock-Leighton Flux-Transport Dynamo to Magnetic Diffusivity Profiles,” Solar Physics, submitted August 2007
Zita, E.J., *Song, N., McDonald, E., Dikpati, M., Influence of depth-dependent diffusivity profiles in governing the evolution of weak, large-scale magnetic fields of the Sun, in Large Scale Structures and their Role in Solar Activity, eds: K. Sankarasubramanian, M. Penn and A. Pevtsov, 18-22 October 2004 @ National Solar Observatory/Sacramento Peak Observatory, Sunspot, New Mexico, USA, ASP Conference Series (2005)
Bogdan, T.J., Carlsson, M, Hansteen, V., McMurray, A, Rosenthal, C.S., *Johnson, M., *Petty-Powell, S., Zita, E.J., Stein, R.F., McIntosh, S.W., Nordlund, Å., Waves in the magnetized solar atmosphere II: Waves from localized sources in magnetic flux concentrations. Bogdan et al., ApJ 599, 626-660 (2003)
Bogdan, T.J., Rosenthal, C.S., Carlsson, M., Hansteen, V., McMurray, A., Zita, E.J., *Johnson, M., *Petty-Powell, S., McIntosh, S.W.; Nordlund, Å., Stein, R.F., and Dorch, S.B.F., “Waves in magnetic flux concentrations: The critical role of mode mixing and interference,” Astronomische Nachrichten 323, 196-202 (2002)
Zita, E.J., A Turbulent Dynamo for Stars Lacking Convection, in Stellar Dynamos: Nonlinearity and Chaotic Flows, ASP Conference Series, Vol. 178, eds. M. Nuñez & A. Ferriz-Mas, (San Francisco: Astron. Soc. of the Pacific), 203 (1999) (Abstract)
Do magnetic waves heat the solar atmosphere? APS poster, Portland, May 2003
Astronomy at Evergreen, a talk given at South Puget Sound Community College, 2003
Magnetic waves in sheared field regions, Banff poster, E.J. Zita, 2002
2002: Magnetic wave transformations in sheared field regions: analytical calculations, presented at the ITP Program on Solar Magnetism and Related Astrophysics at UCSB in January 2002. (Work in progress – last updated 4.Feb.02)
2001: Sun-Earth connections, a talk given at Evergreen
2001: Magnetic effects in peculiar, pulsating stars, in Magnetic fields across the HR diagram, in Magnetic Fields Across the Hertzsprung-Russell Diagram, ASP Conference Proceedings Vol. 248, G. Mathys, S. K. Solanki, and D. T. Wickramasinghe (eds.), (San Francisco: Astronomical Society of the Pacific), p.345
2001: Ringing magnetic stars, a talk given at Kamloops, BC
2000, Magnetic oscillations in radiative stars, in The Impact of Large Scale Surveys on Pulsating Star Research, IAU Colloquium No. 176, ASP Conference Series, Vol. 203, L. Szabados & D. Kurtz (eds.), (San Francisco: Astronomical Society of the Pacific), pp. 386-387
Summer 1998 abstract for Chapman conference on magnetic helicity: Turbulent stellar dynamo for stars without convection
1997, A magnetic model for acoustic modes in roAp stars, in A Half Century of Stellar Pulsation Interpretations, ASP Conference Series, Vol. 135, P.A. Bradley & J.A. Guzik (eds.), (San Francisco: Astronomical Society of the Pacific), pp. 414-422 (pdf format)
1992, MHD computation of feedback of resistive-shell instabilities in the Reversed Field Pinch, Zita, E.J., Prager, S.C., Ho, Y.L., Schnack, D.D., Nuclear Fusion 32, 1941
1992, Turbulent transport in the Madison Symmetric Torus reversed-field pinch, Rempel, T. D.; Almagri, A. F.; Assadi, S.; et al, Phys. Fluids B 4, 7, 2136-2141
Worksheets on Solar Magnetohydrodynamics
Students work these and other derivations with Zita to prepare for summer research. (Thanks to Sara for formatting these.)
- Derive frequencies for plasma oscillations and synchrotron radiation (ref: Chen Ch.4)
- Derive the frozen-in-field condition for conducting plasmas
- Derive the Alfven speed
- Magnetic (resistive) diffusion timescale
- Derive the magnetic reconnection timescale (ref: Tandberg-Hanssen and Emslie Ch.7)
- Scale height
- Dispersion relation for solar p-modes
- Workshops for Astronomy and Sailpower
Papers and web pages by students
Jada Maxwell (TESC), Jiong Qiu and Richard Canfield (MSU), Analyzing Flare Ribbons to Determine Magnetic Reconnection Flux and its Relationship to Flux Rope Formation, American Physical Society NW, Pocatello ID, May 2007
Jada Maxwell, Can Magnetic Waves in the Auroral Region Transform into Acoustic Waves? American Physical Society NW, PLU, Tacoma WA, Ma
Night Song, E.J. Zita, Mausumi Dikpati, Eric McDonald, Influence of depth-dependent diffusivity profiles in governing the evolution of weak, large-scale magnetic fields of the Sun, HAO-NCAR, Boulder, July 2004
Chris Dove, E.J. Zita, Tom Bogdan, Dispersion diagrams of waves in the simulated solar chromosphere, (paper) 2004
Chris Dove, Tom Bogdan, E.J. Zita, Dispersion diagrams of chromospheric MHD waves in a 2D simulation, HAO-NCAR, Boulder, July 2004 (presentation)
An observational analysis of the solar chromospheric intensity, 2003, master’s thesis by Niklas Karlsen, student of Mats Carlsson at the University of Oslo
IDL tutorials, by Matt Johnson, 2002
Oscillators, by Jonathan Gibson, 2000-2001
Observing the Sun at 20.1 MHz: Radio Jove Receiver and Antenna, by Sara Petty-Powell, 2000
Introduction to solar physics, by Caylin Mendelowitz and Claire Rosen, 2000
A proposal for the Evergreen State College Observatory, by Mike Covello, 2000
Observing with the Manastash Ridge Observatory, by Sara Petty-Powell and Andrea Nowicki, 1999
Learning about magnetosonic waves in roAp stars, by Tomoko Adachi with Karen O’Meara, 1998
Magnetic dynamics in the Sun
(This site is under construction)
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 everything to the shared 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.
Magnetic dynamics in other stars
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-runZAMSprogram 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-quality 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.
Fusion is the “good” kind of nuclear energy, generated by an artificial sun in the laboratory. Fusion has the potential to provide much of the world’s electricity without burning fossil fuels. And unlike fission, fusion does not create long-lived, dangerous radioactive sludge. Fusion research is still experimental, though we hope to see commercial fusion reactors in our lifetime. Starting with her undergraduate thesis, Zita worked for a decade in fusion research on tokamaks and other devices designed to confine hot plasma in a “magnetic bottle.” See the excellent web pages for General Atomics and University of Wisconsin – Madison, two premier fusion research facilities.
There has been a surge of funding for fusion research in recent years, facilitating a renaissance in this field. Grad schools are actively recruiting students interested in fusion. Contact Zita if you want to learn more.
Opportunities at Evergreen
- Physics and Astronomy at Evergreen
- Student research: for credit or pay
- Undergraduate research at Evergreen
Please contact Zita by email for details (email@example.com) and put “RESEARCH” in the subject header.
Colleagues and their work…and more links
|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|
|Talks 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 Astronomy and 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) andMONS (Denmark|
|Rattlesnake Mountain Observatory and AASTA||Pacific Northwest National Lab|
|University of Washington-Seattle Astronomy and Manastash 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 sun’s role in climate variations. Science, 296, 673-677. Retrieved May 10, 2005, from http://solar-center.stanford.edu/sun-earth/sun-climate.science020426.pdf
Acknowledgments: 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