Experience

Ø       March 2001– September 2001

Mussoorie Public School, Mussoorie

Post Graduate Teacher - Physics

·         Delivered routine lectures to Intercollege classes

·         Conducted various practicals

Ø       October 2001- Present date

Indian Institute of Geomagnetism, Navi Mumbai

Research Scholar

·         Working on large data sets from several digital magnetic observatories operated by Indian Institute of Geomagnetism and various satellites in space

·         Good hand in data analysis and interpretation of both the data sets. Familiar with several statistical techniques for data analysis

·         Participated in several National/International Conferences (Presented scientific results in form of ORAL/POSTER)

·         Attended National and International Workshops in related themes

·         Annual talks in host institute for assessment of work progress

·         Good knowledge of programming software like FORTRAN, IDL and MATLAB

Education

1993-1995 (Jaswant Modern Sr. Secondary School, Dehradun, Uttarakhand)

·         SSC, C. B. S. E. Board, 69 %

·         HSC,  C. B. S. E. Board, 73.2 %

1998– 2000 (H. N. B. Garhwal University, Shrinagar, Garhwal)

·         B. Sc., Physics, Chemistry and Mathematics, 68.8 %

·         M. Sc., Physics, 67.4 %

2001- till date (Indian Institute of Geomagnetism, Navi Mumbai)

·         Pursuing Ph. D in Physics. Thesis expected to be submitted by July 2008.

Field of Current Research Work

My research area is space weather, which encompasses a wide range of topics dealing with the Earth’s magnetic field, solar magnetic field, plasma from the Sun, transient processes including solar flares, coronal mass ejections (CME) and the most dynamic phenomenon originating through solar-terrestrial interaction, known as ‘Geomagnetic Storms Phenomenon’. The sun releases energy in form of electromagnetic and particle radiations into interstellar space. This stream of charged particles heads towards the Earth, where it experiences an obstruction by the Earth's magnetic field lines. There exists a tear drop shaped cavity within which the Earth's magnetic field is confined, this is called as magnetosphere. There is a transfer of magnetic energy and plasma from the Sun into the magnetosphere of the Earth through the magnetic reconnection of the solar magnetic field lines with the geomagnetic field lines. This tremendous energy fed into the magnetosphere is redistributed into different regions within it. Interaction of highly energetic charged particles with the ambient magnetic field induces various current systems in the magnetosphere namely, magnetopause current, ring current, field aligned current and tail current. The magnetic field of the Earth is changing, as observed from the components H (horizontal), D (declination), Z (vertical) in various ground magnetic measurements. When the energetic plasma emitted from the Sun is injected into the magnetosphere, the regular magnetic field variations are disturbed effectively. This complete duration of disturbance in geomagnetic field variations is called as geomagnetic storm phenomenon, which may last from one day to several days.

Space weather is of utmost importance in terms of socio-economic impacts of the solar-terrestrial interaction for us. Major affect has been born by satellites, telecommunication, power grids and astronauts in the space. Magnetic disturbances also induce electric currents in long conductors such as power lines and pipelines causing power system outages or pipeline corrosion. Proton showers disrupt the satellite coverage by saturation of instruments onboard satellites. Therefore, a good understanding and extensive study of all the processes involved in space weather are mandatory, so as to work for minimizing the hazardous effects. Hence, I got motivated to work on this crucial topic.

Some of the problems addressed in the thesis and the results obtained by studies are briefed below:

(1) To identify the role of zonal (B_y) and meridional (B_z) components of the interplanetary magnetic field for the development of the main phase of magnetic storms.

Our study shows substantial dependence of storm intensity on the two IMF components. Orientation of B_y in association with favourable southward incursion of B_z assists the intensification of the storm strength. We determined the time lag (T_lag) between the onset timings of duskward B_y and southward B_z and found that this T_lag factor can be ascertained as one of the precursory factor for assessing the main phase magnitude and thus the storm intensity (Rawat et al., 2007).

(2) To find out the contribution of duration of IMF B_z for intensification of storms.

Transfer of energy, momentum and flux from the solar wind into the Earth's magnetosphere takes place by the dominant mechanism of magnetic reconnection between IMF B_z and the geomagnetic field lines. Southward B_z enhances the energy transfer process by posing favourable conditions for the occurrence of magnetic reconnection. Our study suggests that sufficient magnitude with prolonged southward orientation of B_z leads to intense main phase in magnetic storms. Another key result obtained is that southward B_z sustaining for considerable duration just before the shock impingement on the magnetopause also supports development of intense magnetic storms (Rawat et al., 2006a).

(3) To determine association of proton events with the geomagnetic storms.

Proton events are produced by the existing heliospheric energetic particle population, which are accelerated and energized by the solar transient processes. They are characterized by enhancement in proton flux at all the energy levels (few keVs to few >100 MeVs).

(i)                  Our study brings out an important conclusion that the SEP events with high flux levels or a “plateau” after the shock passage produce much more intense storms than the events where the SEP flux levels decrease after the shock passage (Rawat et al., 2006a).

(ii)                Study of relative elemental and isotopic abundances in SEP events provides rich information about their origin and history of the populations of energetic ions (Reames, 1999 and Tylka, 2001). Another important result of our work is that large values of isotopic and elemental ratios in the pre-storm periods could contribute substantially towards the intensity of geomagnetic storms which depends largely on the pre-event solar conditions (Rawat et al., 2006b).

Bibliography:

Rawat, R., S. Alex, G.S. Lakhina, Bull. Astron. Soc. India, In press, 2007.

Rawat, R., S. Alex, G. S. Lakhina, Ann. Geophys., 24, 3569, 2006a.

Rawat, R., S. Alex, G.S. Lakhina, Proc. of ILWS Workshop, Goa, 253, 2006b.

Reames, D. V.: Space Sci. Rev., 90, 413, 1999.

Tylka, A. J., J. Geophys. Res., 106, 25,333, 2001.

Participation in National/International Conferences/Symposiums

(1)   Rawat, R., Alex, S. and Lakhina, G. S. Oral Presentation on “Interplanetary and Geomagnetic signatures of three major solar proton events of solar cycle-23” by Prof. S. Alex, at International Union of Geodesy and Geophysics (IUGG), General Assembly, Sapporo, Japan, July 2003.

(2)   Rawat, R., Alex, S. and Lakhina, G. S. Delivered a talk on “Low-latitude Geomagnetic signatures during major solar energetic particle events of solar cycle-23” at IGU, Chennai, December, 2003.

(3)   Rawat, R., Alex, S. and Lakhina, G. S. Delivered a talk and presented a poster on “Geomagnetic signatures associated with intense coronal mass ejections” at National Space Science Symposium, Kottayam, Kerala, 2004.

(4)   Rawat, R., Alex, S. and Lakhina, G. S. Delivered a talk on “Low latitude Geomagnetic signatures following two major solar energetic particle events at different phases of solar cycle-23” at ILWS, Goa, 2006.

(5)   Rawat, R., Alex, S. and Lakhina, G. S. Delivered a talk on “Storm time geomagnetic characteristics at low latitudes under varied interplanetary conditions” at Asia Oceania Geosciences Society 3^rd Annual Meeting, Singapore, July 2006.

(6)   Rawat, R., Alex, S. and Lakhina, G. S. Oral Presentation on “Intense geomagnetic storms and causative interplanetary conditions” by Prof. G. S. Lakhina, at 36^th COSPAR Scientific Assembly, Beijing, China, 2006.

(7)   R. Rawat, S. Alex and G. S. Lakhina. Oral Presentation on “Geomagnetic storm characteristics under varied interplanetary conditions” by Prof. G. S. Lakhina, at International Heliospheric Year-2006, IIA, Bangalore, 2006.

(8)   G. S. Lakhina, Alex, S. and Rawat, R. Oral Presentation on “An Overview of theMagnetosphere, substorms and geomagnetic storms” by Prof. G. S. Lakhina, at I^st Kodai-Trieste Workshop on Plasma, Astrophysics and Space Science, Kodaikanal, 2007.

(9)   Rawat, R., Alex, S. and Lakhina, G. S. Poster presentation on “Double-dip development of storm main phase observed in the low latitude geomagnetic records” at International-Climate And Weather of the Sun-Earth System (I-CAWSES) Symposium held at Kyoto University, Kyoto, Japan in October, 2007.

List of Publications

(1)   R. Rawat, S. Alex and G. S. Lakhina, Low-latitude Geomagnetic Signatures during major Solar Energetic Particle events of solar cycle-23, Annales Geophysicae, vol. 24, 3569-3583, 2006.

(2)   R. Rawat, S. Alex and G .S. Lakhina: Intense geomagnetic storms and causative interplanetary conditions, Under Review in Advances in Space Research, 2007.

(3)   R. Rawat, S. Alex and G. S. Lakhina: Geomagnetic storm characteristics under varied interplanetary conditions, Bull. Astr. Soc. India, 35, 499-509, 2007.

(4)   R. Rawat, S. Alex and G. S. Lakhina: Low latitude Geomagnetic signatures following two major solar energetic particle events at different phases of solar cycle-  23, Proceedings of the International living with star Workshop Proc.,Goa, 253, 2006.

(5)   G. S. Lakhina, S. Alex and R. Rawat, An Overview of the Magnetosphere, substorms and geomagnetic storms, Proceedings of the first Kodai-Trieste Workshop on Plasma, Astrophysics and Space Science Proceedings series, Kodaikanal, Under Review, 2007.