Hari Ramachandran received his B.Tech. from IIT Bombay in 1982 and his
Ph.D. from the University of California at Berkeley, both in Electrical
Engineering. He was a research scientist in the Physics Department at the
University of California, Los Angeles for five years before returning to
India. He was a scientist at the Institute for Plasma Research, Gandhinagar,
from 1993 till 2001 and joined IIT Madras in Nov 2001.
EC 301: Electromagnetic Fields (once a year)
EC 541: Introduction to Fiber Optic Technology (even semesters)
EC 205: CAD Laboratory (odd semesters)
Microwave Lab in charge.
Optical Link Design and Planning
The tenet group has a great deal of experience in the development of Access
level networking systems. This strength lies in the group's expertise in
all the related areas of the technology, including the optical layer, the
electronic subsystems, network management systems and protocols. My own
interests are in the area of the optical physical layer, including both
access links and backbone link design.
Modern optical systems exhibit a variety of interesting phenomena, many
of these nonlinear in nature. My interests are mainly in the areas of
Optical beam propagation in turbulent media, as occurs in terrestrial optical
The interaction between nonlinearity and dispersion.
Solitary wave propagation (ie, solitons) in optical fibres.
We are in the process of developing inhouse a full set of numerical tools
for the investigation of optical communication problems. These include
A Beam Propagation Method code to simulate the propataion of waves
in complex geometries.
A Finite Difference Time Domain code to simulate the transient effects
on optical pulses when they encounter opto-electronic devices.
A Physical Layer Design tool, to study the interaction between different
aspects of link design. This is intended to become a pedagogical tool for
introducing students to the complex world of the optical layer.
Edge Plasma Physics
Plasma Systems are notoriously complex, and never more so than in the edge.
A large part of my work has related to understanding the behaviour of plasmas
in the sheath and presheath. The goals of my research are to understand
better some of the following:
The nature of the ionacoustic wave in the sheath and presheath. To identify
particle and energy transport mechanisms that might be unique to this region.
The nature of the particle distribution function near the sheath region.
The proper forms of fluid equations that are valid in the sheath and presheath.
The sheath-presheath interface.
Computational Plasma Physics
I am developing a particle simulation code to focus on sheath and presheath
physics. Issues that have already been investigated include the identification
of the sheath and presheath about a dust particle, study of wave fluctuations
in an afterglow plasma, the effect of magnetic fields on plasma accretion,
H. Ramachandran, A.J. Lichtenberg and M.A. Lieberman, "A collisional treatment
of the trapped particle mode in multiregion mirror systems," Phys. FLuids
31 (8), August 1988.
H. Ramachandran, G.J. Morales, V.K. Decyk, "Relaxation and Self-Organization
of a Nonneutral Plasma," 1992 International Conf. on Plasma Physics,
Europhysics Conf. Abst. 16c, Part I, page 135.
G.J. Morales and H. Ramachandran, "Role of Alven-Wave Filaments in Tokamak
Transport," 1992 International Conf. on Plasma Physics, Europhysics
Conf. Abst. 16c, Part III, page 1839.
H. Ramachandran, G.J. Morales and B.D. Fried, "Model Study of H-Mode Behavior
Induced by Radial Currents," Phys. Fluids B, 5(3), March
H. Ramachandran, G.J. Morales and V.K. Decyk, "Particle Simulation of Nonneutral
Plasma Behavior," Phys. Fluids B, August 1993.
H. Ramachandran, G.J. Morales, and V.K. Decyk, "Formation of Extended Sheaths
in Nonneutral Plasmas," Proceedings of the International Conference
on Nonneutral Plasmas, San Francisco, Dec 93.
M. Goswami and H. Ramachandran, "A Self-Consistent Kinetic Treatment of
an Unmagnetised Sheath," Proceedings of the Plasma Technology Conference,
IIT, Kanpur, Nov 1995.
Goswami, M. and Ramachandran, H., "A Self-Consistent Analysis of a Collisional
Presheath," Phys. Plasmas 6(12) p 4522 (1999).
Gupta, D.K., Ramachandran, H. and John, P.I., "Spatio-Temporal Measurements
of Trichel Corona Discharge using Capacitive Probe Diagnostic," Review
of Scientific Instruments, Feb 2000.
M. Goswami and H. Ramachandran, "A Self-Consistent Kinetic modeling of
a 1-D, Bounded, Plasma in Equilibrium," Pramana 55(5&6),
page 887 (Nov & Dec 2000).
Sharma, D. and Ramachandran, H, "Self-Consistent Analysis of a Source
Driven Magnetised Presheath," will appear in the Aug 2002 issue of Physical
Sharma, D. and Ramachandran, H., "Revised Boundary Condition to the E×B
drift Dominated Plasma Flow in the Scrap-off Layer," J. Plasma and Fusion
Res. Series, (Proc. 14 Int. Toki Conf, Toki City, Japan) Vol. 3,
Page 218 (2000).
Sharma, D. and Ramachandran, H., "Kinetic Simulation of a Source Dominated
Plasma-Wall interaction in an Oblique Magnetic Field," J. Nucl. Mater.
Vol 290-293, Page 725 (2001).
Rajkhowa, K.R. and Ramachandran, H., "Characteristics of gravitationally
affected colloidal plasma sheath," accepted for publication in Physics of