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Teaching Faculty
Mukul R. Kundu
Mukul Kundu's research interests are primarily in Solar Radio
Astronomy, although in the past he has done extensive research on Galactic
supernova remnants and in Stellar Radio Astronomy. For over four decades
he has been involved in solar radio research, which includes
instrumentation, observation and interpretation of solar radio phenomena
in all spectral domains- from millimeter-centimeter to meter-decameter
wavelengths.He demonstrated the existence of core-halo structure in
sunspot-associated microwave active regions, which led to the development
of low-harmonic gyroresonance radiation.He showed that the same energetic
electrons (hundreds of Kev's) are responsible for microwave and hard
x-ray radiation in solar flares. He wrote the classic book "Solar Radio
Astronomy" which was published in 1965.Using UMD's Clak lake Radio
heliograph at meter-decameter wavelengths he made extensive studies of
coronal streamers, coronal holes, coronal mass ejections and the generation
of different types of radio bursts. In recent years, he used large
interferometers in microwaves such as the Westerbork Synthesis Radio
Telescope (WSRT) and the Very Large Array (VLA) to study solar active
regions including their magnetic fields and solar flares.Using radio
along with soft and hard X-ray imaging data,he mapped the locations
of energetic electrons of different energies in different parts of a
flaring loop. Using the Berkeley-Illinois-Maryland Millimeter Array (BIMA)
at 3 mm along with Compton Gamma Ray Observatory (CGRO) he showed that
MeV-energy electrons are produced in all solar flares, regardless of their
importance. He and colleagues also showed that within the same flaring
loop millimeter-emitting electrons form a distinct population from that
producing microwave and hard x-ray emitting electrons.Using the
Nobeyama Radio Heliograph (NoRH) at 17 & 34 GHz, Nancay Radio Heliograph
(NRH) at metric wavelengths along with Yohkoh Soft X-ray Telescope (SXT),
Kundu discovered both thermal and nonthermal radio signatures of small
scale energy releases on
the Sun, namely coronal X-ray bright point (XBP) flares, X-ray jets,
plasmoid ejections and active region transient brightenings. Kundu and
colleagues found that a class of flares characterized by simple spiky
profiles observed at 17 & 34 GHz with NoRH, and at 86 GHz with BIMA
originated from compact bipolar loops. Kundu and colleagues have been
studying radio evidence of magnetic reconnection in solar flares,using
cases of intersecting flaring loops in microwaves, distinctive
double-loop configuration of a class of microwave flaring sources,and
the evolution of active regions with particular reference to the
interaction between loops as the flare trigger.Such studies are of course
related to flare energy release and acceleration of electrons in solar
flares.
Research Faculty:
Stephen White
Stephen White's interests are solar and stellar radio astronomy and the
astrophysics of the solar corona. His main research involves the use of
several telescopes: observations with the Very Large Array are used
primarily for the study of coronal magnetic fields on the Sun;
observations with the Nobeyama Radio Heliograph in Japan are used to
study solar flares; and observations with the Berkeley-Illinois-Maryland
Array at millimeter wavelengths are used to study solar flares at very
high frequencies where only relativistic electrons can radiate. In
addition, he uses the Australia Telescope to study the famous
massive star Eta Carinae, and is involved in the project to build the
Frequency-Agile Solar Radiotelescope (FASR), the next-generation
solar-dedicated radio telescope that will be designed for studies of
solar flares, coronal mass ejections and coronal magnetic fields.
Victor Grechnev
Victor Grechnev's research interests are primarily in solar radio
astronomy, the astrophysics of the solar corona, and solar data analyses.
In the past several years he has been involved in instrumentation ;and he contributed
to the development of the Siberian Solar Radio Telescope in Russia.
As a member of the SSRT team, he contributed to studies of microwave
millisecond spikes in solar flares and experimental
finding of anomalous scattering of centimetric radio emission in the
lower corona. In recent years he extensively used data of the Nobeyama Radio
Heliograph at 17 & 34 GHz along with solar data in other spectral domains. He
contributed to several studies of solar flares, active regions, coronal holes,
and coronal mass ejections. He has shown that a solar impulsive flare can be
actually caused by interactions of closed loops even if apparent features
attributed to a popular open field line model of solar flares are present.
V. Grechnev has made important contributions to data analyses using IDL softwares.
Postdoctoral Researchers:
Vladimir Garaimov
Vladimir Garaimov's research interests are solar radio
astronomy, the physics of the solar corona, and solar data analyses.
In recent yaers he extensively used data of the Nobeyama Radio
Heliograph at 17 and 34 GHz along with solar data received from satellites.
V. Garaimov has made important contributions to data analyses using IDL softwares and C++.
In the past, he developed software
package for
RATAN-600 solar data analysis.
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