IACS Personnel

Institute for Astrophysics and Computational Sciences
http://iacs.cua.edu

Nat "Gopal" Gopalswamy

Position: Research Professor, IACS, Catholic University of America
Mail Address: NASA/Goddard Space Flight Center, Code 682.3, Greenbelt, MD 20771
Office Location: GSFC, Bldg. 26, Room G-1
Phone (GSFC): 301-286-5885
Fax (GSFC): 301-286-0264
Email: gopals@fugee.gsfc.nasa.gov

A Prominence Eruption in Microwaves

Sequence Time: 23-NOV-1992 02:28:43 TO 23-NOV-1992 03:40:43
Full size (442.28 KB)

The above is a movie of material ejection from the Sun at a speed of about 200 km/s. These eruptions are associated with large-scale disruption of the solar atmosphere which can result in huge effects on the Earth's environment if directed towards the Earth. The images were obtained by the Nobeyama Radioheliograph in Japan which observes the Sun daily at 17 and 34 GHz for 8 hours, providing images of flares, prominence eruptions and a host of other activities on the Sun.

Research Interests:

Dr. Gopalswamy is a Solar Radio Physicist involved in the study of eruptive phenomena from the Sun such as coronal mass ejections, shock waves and prominence eruptions. He uses a number of data sources for his research such as the Very Large Array in New Mexico, the Nobeyama Radioheliograph in Japan, the Yohkoh, SOHO and WIND spacecraft. Current areas of interest include the following:

1) Onset Phase of Coronal Mass Ejection . Coronal Mass Ejections are large-scale eruptions from the Sun consisting of hot and cold material and magnetic fields. When the ejection is earth-directed, there is a very good chance that they cause geomagnetic storms and other potentially harmful effects on the earth-based and space-borne technological systems. Dr. Gopalswamy is engaged in the study of the origin of these CMEs. He studies X-ray arcade formations which are like "scars" left behind by the CMEs; filament eruptions that accompany the CMEs and various bursts of radio emissions caused by the CMEs as they propagate into the interplanetary medium. He is also interested in establishing the connection between CME manifestations in the near-Sun and near-Earth domains of the space.

2) Origin of Coronal and Interplanetary shocks There is a long-standing controversy regarding the origin of coronal and interplanetary shocks. Some researches say that both coronal (shocks close to the solar surface) and interplanetary (in the interplanetary medium beyond several solar radii) are driven by CMEs. Others say that flare drive both kinds of shocks and that both kinds of shocks are one and the same. There is yet another view that coronal and interplanetary shocks are of independent origin. It is important to clarify this issue so that space observations can be effectively utilized in forecasting space weather.

3) The Magnetic Nature of Coronal Holes: Coronal holes are regions of lower density and temperature containing open magnetic field lines. High speed solar wind originates from the coronal holes and hence serves as a laboratory to study the heating and acceleration of solar wind. While emissions at most other wavelengths are diminished compared to other parts on the Sun, the coronal hole shows enhanced radio emission in microwaves. Dr. Gopalswamy is investigating this peculiar phenomenon which may provide additional clues to understand the origin of solar wind. He has recently found that the radio enhancement is associated with the enhanced unipolar magnetic flux elements in the coronal hole.

4) Small-scale Energy Releases on the Sun: Dr. Gopalswamy and his co-workers recently discovered a phenomenon called the Transient Microwave Brightenings" at the peripheries of sunspot umbrae. These are small-scale energy releases which may be the elementary processes by which the coronal plasma in active regions is heated. The contribution of these brightenings to the total amount of heating needed to maintain the solar corona at the million-degree level is being investigated.

Yohkoh-SOHO coordinated Data Analysis Workshops:

CDAW 1- 1997 February 07 CME

CDAW 1 - 1997 January 06 CME

CDAW 2

CDAW 3

CDAW3 movies

ISTP-IACG Workshop on Solar Eruptive Events

International Conference on Solar Eruptive Events

Recent Papers/Preprints:

"The Astronomical Low Frequency Array (ALFA): Imaging from Space", Gopalswamy, N.; Kaiser, M. L.; Jones, D. L.; The Alfa Team, Solar Physics from Radio Observations, Eds.: T. S. Bastian, N. Gopalswamy and K. Shibasaki, NRO Report No. 479., p.447-451

"Type II solar Radio Bursts (A tutorial Review)," N. Gopalswamy, AGU monograph 119 - Chapman Conference on Space-Based Radio Observations at Long Wavelengths, 2000, p. 123.

"X-ray and Microwave Signatures of Coronal Mass Ejections", N. Gopalswamy, Solar Physics from Radio Observations, Eds.: T. S. Bastian, N. Gopalswamy and K. Shibasaki, NRO Report No. 479., 141

"Near-Sun and Near-Earth Manifestations of Solar Eruptive Events", N. Gopalswamy, A. Lara, M. L. Kaiser and J.-L. Bougeret, JGR, in press, 2000.

"Early Life of Coronal Mass ejection," N. Gopalswamy and B. J. Thompson, JASTP, in press, 2000

"Structure and Dynamics of the Corona surrounding Eruptive Prominences," N. Gopalswamy, Y. Hanaoka and H. S. Hudson, Adv. Space Res, 25 (9), 1851, 2000.

"Photospheric Magnetic Field Changes During Coronal Mass Ejections", A. Lara, N. Gopalswamy and C. E. DeForest, GRL, 27, 1435, 2000.

"Radio-rich Solar Eruptive events", N. Gopalswamy, M. L. Kaiser, B. J. Thompson, L. Burlaga, A. Szabo, A. Lara, and A. Vourlidas, GRL, 27, 1427, 2000.

"Interplanetary Acceleration of Coronal Mass Ejections", N. Gopalswamy, A. Lara, R. P. Lepping, M. L. Kaiser, D. Berdichevsky, O. C. St Cyr, GRL, 27, 145, 2000.

"X-ray and radio manifestations of a solar eruptive event," N. Gopalswamy, N. Nitta, P. K. Manoharan, A. Raoult and M. Pick, Astron. Astrophys., 347, 684, 1999.

"Microwave enhancement and variability in the Elephant's Trunk coronal hole: Comparison with SOHO observations ", N. Gopalswamy, K. Shibasaki, B. J. Thompson, J. B. Gurman, and C. DeForest, JGR, 104, 9767, 1999

``Origin of Coronal and Interplanetary Shocks: A new Look with WIND Spacecraft Data'', N. Gopalswamy, M. L. Kaiser, R. P. Lepping, S. W. Kahler, K. Ogilvie, D. Berdichevsky, T. Kondo, T. Isobe and M. Akioka, JGR, 103, 307, 1998.

``X-Ray and Radio Studies of a Coronal Eruption: Shock Wave, Plasmoid, and Coronal Mass Ejection'', N. Gopalswamy, M. R. Kundu, P. K. Manoharan, A. Raoult, N. Nitta, and P. Zarka, ApJ, 486, 1036, 1997.

Full List of Publications
A Summary of Research Accomplishments

Additional Information:

Curriculum Vitae
Some Recent Collaborative Efforts
A List of VLA Observing Proposals