Characteristics of Storm Time Pulsations at Magnetic Meridional Plane Connecting Conjugate Stations Raman Selvamurugan, Ajay Dhar, and Arun Hanchinal Indian Institute of Geomagnetism, Plot#5, Sec-18, Kalamboli Highway, New Panvel, Navi Mumbai – , INDIA also at

Currents above and around the Globe  Magnetic field (IMF) associated with solar wind ( ) - opens the filed lines for the entry of solar wind  Solar wind particles – Influence the Currents – also generates shock waves – that resonate with the earth’s magnetic field Solar wind pressure = terrestrial pressure of the Magnetic field

Case – I Dst = -363 nT Case – II Dst = -373 nT Tromso (69 40 N, E) Maitri (70 45’ S, E)

Caution: Scales are Different ! Indices

Interplanetary conditions

Inter planetary Conditions Contd.

Amplitude (nT) At Maitri ULF pulsations

PC5 pulsations at different latitudes Locations Maitri Pondicherry Hanley

Continued for Pc6

Continued for longer periods at different latitudes

During 20 th Oct-10 th Nov, 2003

At longer periods

Disturbance field amplitude at various time scales Corresponding to the magnetic storm day

Case – I

Time

Physical conditions at Maitri and other stations

Case II

Q-day Characteristics

The basis for the proposal  The phase drift corresponding to sub storm pulsations between the conjugate pair of stations is found to appear even before a well defined storm occur.  The emphasize remains on the early drift in phase behavior which is found to happen even before the initial phase of the storm.  The phase at these two conjugate stations during the peak of the storm is found to be exactly in out of phase manner.  Subsequently the phase difference gradually decrease between these stations and attains a phase coherence with each other.  The pulsation amplitudes maximizing at minutes indicate that the sub storm processes are rather more intense than the storm time field line resonance modes excited by IMF shocks during storm.  Pulsation at different wave disturbance band at different latitude suggests that the field line resonances are more intense at higher latitudes.  Absolute values of earth’s horizontal component seem to relate to the strength of the storm, whereas the phase and amplitude information of a dominant/sensitive time scale disturbances would provide exact time at which the initial, growth and recovery phase of the storm takes place.

What we need to understand! How the field line resonances in terms of its amplitude and phase changes as we move from high latitude to low latitude along the same magnetic meridian? What are the longitudinal (magnetic!) in equalities in the propagation modes? Can we predict the Storm using only the ground based magnetic sensors? How Auroral current responds to the storm?

Magnetic field line trace along 150º Meridional plane

Indian Magnetic observatories

Indian Stations along 150 Magnetic Meridians Existing Proposed

Moscow Mys Zhelaniya Rudolfa Mumbai North pole highest lowest Jan -10ºC -15º C Jul 0.0ºc +2.2º C 30 y +13º C -54º C

North pole town

Hobart

Approach to the new location to the ANTARCTICA STATION highest lowest Jan 9.2ºC -8.9º C Jul 1.1ºc -33.2º C

Expedition route to Antarctica

3 axis flux gate sensor, Exciter, LNA, AA-Filter, channeled Analog output from the Sensor Choosing a flux gate magnetometer Typical standards that are Required Bandwidth Dc- 1 Hz Range ± 70,000 nT Resolution 0.1 nT Sensitivity <10.0 pT/Hz Accuracy 0.1 nT Long term stability 0.1 nT power consumption <2.5 W Op Temp/drift 0.1 nT/C D/A Converter, Digital Filters (All the channels) Data Acquisition standalone hardware/or a PC recording all channels RS 232/RS485 Data storage Software/ Hardware Intermediate for monitoring Interface

Existing Magnetometers and their outputs Digital Flux gate H, D, Z or δ X, δ Y, δ Z DI flux gate D, I PPM F Variometers X, Y, Z Intermagnet (DFM) X, Y, Z, F dIdD suspended δ D, δ I, F, or X, Y, Z Digital magnetometer X,Y,Z Vector PPM F, H, Z

S No Type of instrument Resoluti on RangeComponent measured BandwidthAccur acy Tem p Drift / ºC Long term drift Temp range in C/Remark s 1Intermagnet (standard) 1 nTBase value ±3000 nT F, δ X, δ Y, δ Z, X, Y, Z DC – 10 Hz0.1 nT1 nT 2DI flux Magnetometer 0.1 nT0.1 nT- 200,000 nTD, IDC- 10 Hz0.1 nT0.01n T < PPM0.1 nT70,000 nTFDC-2 MHz nT 0.01 nT Insensiti ve to changes in temp PGR Hz/nT 4Variometers0.1 nT1-60,000 nTX, Y, Z1 nT 5Digital Flux gate0.1 nTBase value ±3000 nT H, D, Z or δ X, δ Y, δ Z, DC-1 Hz0.1 nT<0.1 nT 6dIdD suspended overhauser magnetometer 0.01 nT20, ,000 nTF, dI, dD or X, Y, Z DC-5Hz 1-5s 0.2 nT2 nT Digital magnetometer (STL) nT ±80,000 nT – ±100,000 nT X, Y, Z0.05 Hz-4 kHz (100µ s-20 s) <0.1 nT <0.2 nT <0.1 nTTemp range?/Mo unting?/S ensor alignment 8Vector PPM0.1 nT70,000 nTF, H, ZDC-2 MHz0.1 – 0.01 nT Insensiti ve to changes in temp

Low power acquisition Wireless acquisition

Budget Requirement S.NoItemsI Year (Rs in lakhs) 1.Junior Research Fellow Cost of running Network of sensors with new installations Computational equipment Procurement of magnetometers Travel Consumables Telephone, Fax, Internet charges Contingencies Cost of Minor equipment/computer facility upgrading NA 10.Total67.80 Thank you