1. science
2. physics

Stability studies on some hydro-magnetic and other waves in a pair ion plasma with a
third species of ions: cometary applications
(i)
Preamble:
In two computer simulation experiments in 2010 and 2013 it was conclusively shown that
the crash of a comet on rocky surfaces was all that was needed for seeding planets (and
their satellites) with amino acids – the basic building blocks so essential for the development
of life. Very recently, it was demonstrated experimentally for the first time in a laboratory
that amino acids are indeed produced by mimicking the impact of a rocky body on an icy
surface. Mankind, since early times, has always been puzzled about the origin of life on the
surface of the earth. The studies and experiment mentioned above have put comets at the
forefront for an answer to this long standing puzzle.
(ii)
Issues of Focus:
It has thus become imperative that we thoroughly understand all features of a comet – their
physical structure, nature, composition and dynamics of it’s atmosphere, etc. Since the
atmosphere around a comet can be expected to be ionized to a large extent (especially
when it is nearer the Sun), the importance of understanding plasma processes in a cometary
environment needs no special emphasis.
(iii)
Objectives / Research Focus:
One important tool for understanding plasma processes is to study the propagation and
stability of waves propagating in that plasma. We therefore propose to study, both
analytically and numerically, the propagation and stability of four different waves that have
been observed in cometary environments.
(iv)
Reasons and Justification:
As mentioned above, comets are now at the forefront as agents responsible for the origin of
life on our earth. Since it is not easy to mimic a cometary atmosphere in the laboratory we
will study, theoretically and computationally, the propagation and stability of some of the
waves that were observed in cometary plasmas by satellites.
(v)
Deliverables:
The importance and necessity of this study has already been mentioned in section (iii).
Besides satisfying a scientific curiosity about an astronomical object that is suddenly in the
limelight, we hope to make significant contributions to the growing literature on the various
plasma processes in cometary environments.
(vi)
Work Plan:
Hydro-magnetic turbulence in plasma environments of comets was anticipated on
theoretical grounds by Ip and Axford in the early 1980s. And this turbulence in the form of
Alfven waves was detected by ICE (International Cometary Explorer) satellite at the comet
Giacobini-Zinner [1]. Similar turbulence was also observed at comet Halley by the
spacecrafts Giotto and Vega [2, 3].
It is generally now accepted that a cometary plasma contains hydrogen (H) and newborn
heavier ions such as positively charged oxygen (O+). However, Chaizy et al [4] observed
negatively charged oxygen (O-) also in the coma of comet Halley, which was an unexpected
discovery. Some of the plasma waves that have been systematically studied by the Plasma
Physics Group at the School of Pure & Applied Physics, Mahatma Gandhi University in
relation to such plasma environments are the lower hybrid wave, lower hybrid drift wave,
the electrostatic ion cyclotron wave, the ion acoustic wave and the kinetic Alfven wave [5 –
13].
Low frequency turbulence, in the frequency range of 10 – 300 Hz, has been observed in the
plasma environment of comet Halley. Wave studies in a H – O+ plasma have been carried
out by a number of authors and the results have been applied for the explanation of these
waves. However, as mentioned above, O- has also been observed.
First Phase:
The discovery of O- ions allows one to model a cometary plasma as a pair-ion plasma with
hydrogen as a third constituent.
We thus propose to study the stability of Alfven waves in such a plasma. Dispersion
relations will be derived and it’s stability computed for typical parameters.
We will also study the stability of the kinetic Alfven waves. While a certain amount of work
has already been carried out, the parameter space was restricted to get the equations in a
compact form. A complete numerical study would thus extend our analytical results while
at the same time exploring a larger parameter space.
Second Phase:
We also propose to extend our investigations on the stability of obliquely propagating
lower hybrid waves in a plasma environment containing positively charged oxygen (O+) and
negatively charged oxygen (O- ) ions as the pair ions with hydrogen (H+) and electrons
streaming parallel to the magnetic field. Since we are considering oblique propagation, the
six independent elements of the dielectric tensor have to be derived for all the species to
set up the dispersion relation. An attempt will be made to solve the dispersion relation
analytically which is expected to be complicated. A numeric study of the dispersion relation
of the dispersion relation will also be made to complement the analytic study.
Third Phase:
The fourth problem that we propose to consider is the stability of the right and left
circularly polarized wave in a plasma of the same composition. We expect to observe
additional cut-offs and resonances in this 3 ion plasma as compared to a two ion plasma of
hydrogen and positively charged oxygen ions.
References
[1] B T Tsurutani and E J Smith (1986) Geophys. Res. Lett. 13 259
[2] F Neubauer, K Glessmeier, M Pohl et al (1986) Nature 321 352
[3] W Reidler, K Schwingenschuh, Y G Yeroshenko et al (1986) Nature 321 288
[4] P H Chaizy, H Reme, J A Sauvaud et al (1991) Nature 349 343
[5] Chandu Venugopal, M J Kurian, C P Anilkumar, S Antony & G Renuka (2006) Physica
Scripta 73 389
[6] Chandu Venugopal, M J Kurian, V K Premnadh & G Renuka (2007) Ind. J. Phys. 81 445
[7] Chandu Venugopal, M J Kurian, S Antony, C P Anilkumar & G Renuka (2007) Physica Scripta
75 682
[8] M J Kurian, S Jyothi, S K Leju, Molly Isaac, Chandu Venugopal & G Renuka (2009) Pramana
– J. Phys 73 1111
[9] Chandu Venugopal, M J Kurian, Savithri Devi E, P J Jessy, C P Anilkumar & G Renuka
(2010) Ind. J Phys. 84 319
[10] Samuel George, Savithri Devi E & Chandu Venugopal (2011) Plasma Sci. & Tech. 13 135
[11] Chandu Venugopal, Savithri Devi E, Jayapal R, Samuel George, S Antony & G Renuka (2012)
Astrophysics & Space Science 339 157
[12] Noble Abraham, Sijo Sebastian, Sreekala G, R Jayapal, C P Anilkumar & Chandu Venugopal
(2013) Journal of Astrophysics, Article Id 838534 doi:10.1155/2013/838534
[13] Noble Abraham, Sijo Sebastian, Sreekala G, Savithri Devi E, G Renuka & Chandu Venugopal
(2013) Astrophysics and Space Science (in Press)
(vii)
Programme schedule, including activity diagram/ Bar chart:During the first six months of the first year we propose to derive the dispersion relation and
investigate the stability of Alfven waves in a multi-ion plasma that specifically contains Oions since the discovery of these ions was an unexpected one and enables one to model a
cometary plasma as a pair ion plasma with hydrogen ions as a third constituent.
In the latter half of the first year we propose to investigate numerically the stability of
kinetic Alfven waves in a multi-ion plasma. The analytic expressions have already been
derived and what remains is an exhaustive numerical investigation of the full parameter
space.
During the second year we propose to investigate the stability of lower hybrid waves in a
pair-ion plasma; the other constituents being hydrogen and electrons. Since we propose to
include all the six independent elements of the dielectric , derivation of the dispersion
relation is expected to be tedious and time consuming.
Finally, during the first half of the third year, we propose to consider the stability of the
right and left circularly polarized wave in multi-ion cometary plasma. The addition of
negatively charged oxygen ions is expected to introduce additional cut-offs and resonances
when compared to a two ion plasma of hydrogen and positively charged oxygen ions.
The final reports will be prepared during the second half of the third year.
(viii)
Budget:
Description of Budget Head
(a) Staff
JRF
Reqd.No.
SRF
Reqd.No.
RA
Reqd.No.
1
Emeritus Scientist Allowance
Subtotal
(b) Contingency
Chemicals, samples, glassware
etc.
Maintenance
Information Search (from
databases)
Travel
Any other
Subtotal
1st Year
2nd Year
3rd Year
2.64
2.64
2.64
2.40
2.40
2.40
5.04
5.04
5.04
0
0
0
0
0
0
0
0
0
0.50
0.25
0.50
0.25
0.50
0.25
0.75
0.75
0.75
5.79
5.79
(c) Equipment (itemwise)
1.
Work Station
3.0
2.
Printer
0.2
3.
4.
5.
Subtotal
(d) Total
(e) Total Cost of the
Project
3.2
8.99
20.57
(ix) Outcomes and Outputs:
The proposed study is expected to lead to a deeper understanding of the propagation
characteristics of some important waves in a cometary plasma environment. The results are
expected to lead to a deeper understanding of the dynamics and composition of a
cometary atmosphere.
For the last seven years we have been systematically studying wave propagation and
stability in a cometary plasma environment. Some of the important publications related
to this area are given below.
(x) List of publications with full bibliographic details:
Total number of publications : 70.
(Only publications during the last 5 years are given below; those related to the proposed
project are indicated by a *)
1. Apposite of atmospheric electric parameters with the energy coupling function (ε)
during geomagnetic storms at high latitude
C P Anilkumar, C Panneerselvam, K U Nair, C Selvaraj , S Gurubaran
&
C
Venugopal
Atmospheric Research (2009) 91 201 – 205 (I F: 2.20 Citations: 1)
2.
*
3.
*
4.
Stability of electrostatic ion cyclotron waves in a multi-ion plasma
M J Kurian, S Jyothi, S K Leju, Molly Isaac, Chandu Venugopal & G Renuka
Pramana - J. of Physics (2009) 73 1111 – 1122 (I F: 0.57 Citations: 0)
Low frequency electromagnetic waves in a multi-ion plasma
Chandu Venugopal, M J Kurian, Savithri Devi E, P J Jessy, C P Anilkumar
Renuka
Ind. J Physics (2010) 84 319 – 324 ((I F: 1.78 Citations: 8)
&
G
*
Kinetic Alfven waves excited by cometary new born ions with large perpendicular
energies
Samuel George, Savithri Devi E & Chandu Venugopal
Plasma Science and Technology (2011) 13 135 – 139. (I F: 0.51 Citations: 0)
5. Seasonal and solar activity dependence of storm time TEC variation for a low latitude
station Palehua
P K Subhadra Devi, K Unnikrishnan & C Venugopal
J. Atmos. Solar and Terr. Phys. (2011) 73 1687 – 1696 (I F: 1.42 Citations: 0)
6.
*
The influence of negatively charged heavy ions on kinetic Alfven wave in a cometary
environment
Chandu Venugopal, Savithri Devi E, Jayapal R, Samuel George, S Antony & G Renuka
Astrophysics and Space Science (2012) 339 157 – 164 (I F: 2.06 Citations: 0)
7. Electrostatic ion waves in a magnetised, collisional multi-ion plasma
Samuel George, Rajeev V R, Neethu Theresa Willington, R Jayapal, S Antony & C
Venugopal
Proc. 27th PSSI National Symposium on Plasma Science & Technology (Plasma -2012), Ed
Suraj Kumar Sinha, Excel India Publishers, New Delhi, (2013) 96 – 100 (ISBN 978-9382062-82-0)
8.
*
Dispersion characteristics of kinetic Alfven waves in a multi-ion cometary plasma
R Jayapal, Savithri Devi E, Blesson Jose, S Antony, C P Anilkumar & Chandu Venugopal
ibid 471 – 475.
9. Electron cyclotron instabilities driven by ion beams perpendicular to the magnetic field
Noble P Abraham, Samuel George, Sijo Sebastian, Anju Sreekumar, Aswathy V, Sreekala
G & Chandu Venugopal, ibid 479 – 483
10. *Stability of electron cyclotron waves in a multi-ion plasma
Noble P Abraham, Samuel George, Blesson Jose, Sijo Sebastian, C P Anilkumar & C
Venugopal, ibid 484 – 487
11. Plasma electron temperature variability in lunar surface potential and in electric field
under average solar wind conditions
S B Rakesh Chandran, G Renuka & Chandu Venugopal
Adv. Space Res. (2013) 51 1622 – 1626 (I F: 1.18 Citations: 0)
12. *Ion-acoustic instabilities in a multi-ion plasma
Noble P Abraham, Sijo Sebastian, Sreekala G, R Jayapal, C P Anilkumar & Chandu
Venugopal
Journal of Astrophysics (2013), vol. 2013, Article Id 838534 doi:10.1155/2013/838534
13. Stability of the magnetosonic wave in an anti-loss cone plasma
Chandu Venugopal, Samuel George, V R Rajeev, R Jayapal, M J Kurian & C P Anilkumar
Ind. J Physics (2013) 87 939 – 945 (I F: 1.78 Citations: 0)
14. *Stability of ion acoustic waves in a pair-ion plasma with a third species of ions:
Application to cometary plasmas
Noble P Abraham, Sijo Sebastian, Sreekala G, Savithri Devi G, G Renuka & Chandu
Venugopal
Astrophysics and Space Science (2013) (in Press) (I F: 2.06 Citations: 0)
(xi): Summary of proposed research:
The discovery of negatively charged oxygen ions (O-) allows one to model a cometary
plasma as a pair-ion plasma of positively and negatively charged oxygen ions (O+ and Oions). Electrons and hydrogen ions are the other constituents of our plasma. We intend
studying the stability of the Alfen wave, the kinetic Alfven wave, the lower hybrid wave and
circularly polarized waves in such a plasma. Pair ion plasmas were first produced in the
laboratory in 2005. Though this proposal will be mainly devoted to astrophysical
applications, they can easily be adopted to laboratory pair ion plasmas as well.