11.the response of interplanetary medium to the geomagnetic storm of april 2010www.iiste.org call for paper

  • 556 views
Uploaded on

 

More in: Technology
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
    Be the first to like this
No Downloads

Views

Total Views
556
On Slideshare
0
From Embeds
0
Number of Embeds
0

Actions

Shares
Downloads
4
Comments
0
Likes
0

Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
    No notes for slide

Transcript

  • 1. Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol 4, 2012 The Response of Interplanetary Medium to the Geomagnetic Storm of April 2010 R.O Salami* 1,2 A.B Rabiu2,3 E.O. Falayi2,4 F.O Oluyemi2,5 1 Dept of Physics, Afe Babalola University, Ado-Ekiti, Nigeria 2 Space Physics Laboratory, Federal University of Technology, Akure, Nigeria 3 National Space Research & Development Agency, NASRDA, Abuja, Nigeria 4 Dept of Physics, Tai Solarin University of Education, Ijagun, Nigeria 5 Dept of Physics, Federal Polytechnic, Ado-Ekiti, Nigeria *e-mail of the corresponding author: olawunmmisalam@yahoo.com Abstract Knowledge of the activities within our own solar system is of fundamental importance in our attempts to understand the processes that occur in the upper reaches of our atmosphere; because, space weather is greatly influenced by the speed and density of solar wind and Interplanetary Magnetic Field (IMF) carried by solar wind plasma. For this reason, behaviours of the interplanetary medium during the storm of 5-7 April 2010 were examined using the routinely observed values of southward component of the Interplanetary Magnetic Field, Bz, Disturbance storm time Index, Dst, Solar Wind Speed. Data of H and Z components of the Earth’s magnetic field recorded at some equatorial and polar stations were also considered to investigate ionospheric responses to the storm. Strong solar wind hit the Earth’s magnetosphere about 0800UT on 5 April 2010 and sparked first geomagnetic storm of the new solar cycle. The storm was the largest geomagnetic storm of the Sun caused in the past three years. The commencement, main phase, and recovery phase of the storm were discussed vis-à-vis response of the interplanetary medium. Probable magnetic processes responsible for the storm as well as the ionospheric implications were also highlighted. Keywords: Geomagnetic storm, interplanetary magnetic field, solar speed and disturbance storm time index 1.0 IntroductionSpace weather describes the interaction between the Sun and Earth. Storms on the Sun can produce bursts ofcharged particles. These shoot out into space, and sometimes end up hitting the Earth. The effects of solarstorms can be as beautiful as an aurora or can cause damage to the satellites and health risks to astronauts andaircraft crews. Meanwhile, our modern lifestyle depends heavily on space technology, for example, for TVand mobile phone communications, internet. We cannot prevent geomagnetic disturbance, but we canmonitor the Sun and give some warning when stormy weather is approaching the Earth. Hopefully,appropriate action can be taken to limit any damage. Thus, the physical phenomena which are associatedwith space weather such as the speed and density of the solar wind, the interplanetary magnetic field (IMF)carried by the solar wind plasma and geomagnetically induced currents at Earths surface must be consideredat every time interval.One of the disturbances that can be monitored on Earth to provide estimates of the level of themagnetospheric activity is the Disturbance Storm Time Index, Dst. Dst is a geomagnetic index which monitors the world wide geomagnetic storm level. It is constructed byaveraging the horizontal component of the geomagnetic field from mid-latitude and equatorial magnetogramsfrom all over the world. Negative Dst values indicate a geomagnetic storm is in progress, the more negativeDst, the more intense the geomagnetic storm. The negative deflections in the Dst index are caused by thestorm time ring current which flows around the Earth from east to west in the equatorial plane. The ring 28
  • 2. Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol 4, 2012current results from the differential gradient and curvature drifts of electrons and protons in the near Earthregion and its strength is coupled to the solar wind conditions. Geomagnetic storms as seen in Dst commonlyhave three phases: a sudden commencement, a main phase and a recovery phase. (Burton et al, 1975). Thesudden commencement occurs as the initial impact of increased solar wind dynamic pressure sharplycompresses the magnetopause. At the ground, this is observed as a sharp increase in horizontal magnetic fieldintensity on time scales of less than 1h. The main phase and recovery phases are characterized by a decreasein horizontal magnetic field intensity and then slow return to baseline. The strength of a geomagnetic stormis described by the minimum reached during the main phase (Gonzalez et al., 1994).Another disturbance that can be monitored on Earth to provide estimates of the level of the magnetosphericactivity is the southward component of the interplanetary magnetic field, Bz. The southward component of theinterplanetary magnetic field, Bz has been associated with geomagnetic activity in general (Foster et al.,1971) and the geomagnetic storm main phase in particular (Russel et al., 1974). Rostoker and Falthammar, (1967) found that the storm main phase was associated with a sustainedsouthward, Bz. Russel et al., (1974) found that the southward, Bz had to exceed an apparent threshold level,possibly Dst -dependent, in order to trigger a storm main phase. Rostoker and Falthammar, (1967) also notedthe recovery phase was associated with a decrease or switching off of the southward, Bz.Also, ground-based magnetic field observations have a component that is reflective of the Earth’s spaceenvironment and provide important information about the state of geomagnetic activity. The competingbalance between Earth’s intrinsic magnetic field and solar wind dynamic pressure drives much of thevariation of the Earth’s space environment three independent elements are required to specify the magneticfield at any location (Ganon and Love, 2010). The field is specified either by rectangular components X, Yand Z or H, D and Z. These components are being measured at various magnetic observatories all over theglobe (Rabiu, 2000). In this paper, we looked at the H and Z component of the Earth magnetic field for themonth of April and the inductance during the geomagnetic storm period.2.0 Data CollectionFor the present work we have studied geomagnetic storm of April 2010 which occurred between 5 and 7April 2010. The studying parameters are southward component of the interplanetary magnetic field, Bz ,disturbance storm time index, Dst and solar wind speed. The data were taken from OMNIWEB(omniweb.gsfc.nasa.gov/ow.html) at 1hour interval over 30 days. While the X, Y, Z components of theearth’s magnetic field data were obtained from Intermagnet Geomagnetic Observatory at one minute interval. STATION’S NAME LAT (o) LONG (o) HIGH LAT Baker Lake 64.319 96.10 MID LAT Tucson 32.181 110.58 EQUATOR Guam 13.590 144.45 Table 1: Geomagnetic Observatory and their Coordinate 29
  • 3. Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol 4, 20123.0 MethodologyThe southward component of the interplanetary magnetic field, Bz, disturbance storm time index, Dst andsolar wind speed hourly values for all the days of April 2010 were plotted against universal time. The X , Y,Z values of the Earth magnetic field at the polar, mid-latitude and equatorial stations collected at one minuteinterval were averaged to hourly values for all the days of April 2010. And the H component values of theEarth magnetic field for all the days of April 2010 were obtained following equation 1.1. H = (X 2 +Y 2 ) 1.1X - The component of the Earth along horizontal geographic north;Y - Horizontal geographic east componentsH - Horizontal intensity; the horizontal magnetic intensity due to the X and Y component;3 .1 InductanceThe inductance of the of the storm time from 4th-9th of April 2010 were determined using equations (3.1 –3.3)3.1.1 Midnight Baseline Value, HoMean of 4 hourly values of each magnetic components flanking local midnight values (Rabiu et al, 2007 andChandra et. al., 2000). H5 + H6 + H7 + H8For the high latitude station: H O = 4 H6 + H7 + H8 + H9For the mid latitude station: H O = 3.1 4 H 9 + H 10 + H 11 + H 12For the equatorial station: H O = 43.2 Hourly DepartureHourly departure from the midnight value of time, t at local time (LT) were analysed by subtracting midnightbaseline value from each hourly values t1 to t24 hour for each of the component from 4th-9th of April 2010. δH = H t − H o 3.2 30
  • 4. Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol 4, 2012The ZO and δZ were determined according to equations (3.1 and 3.2), then the inductance were foundusing equation 3.3 δZ δI = 3.3 δH4.0 Results and Discussions4.1 Hourly Variations of Interplanetary Indices & H with Dst Figure 1a shows the hourly average plot of, Bz, solar wind speed and Dst. A sudden increase in the value of Bz was seen just before the sudden commencement of the storm. The value increased from 0.1nT at 10:00UT to -11.4nT at 11:00UT on April 5 2010. An hour later, solar wind speed increased from 730km/s at 12:00UT to 783km/s at 13:00UT. The southward component of the interplanetary magnetic field, Bz, causes magnetic reconnection of the dayside magnetopause, rapidly injecting magnetic and particle energy into the Earths magnetosphere. Thus, leading to sudden increase in solar wind speed which compresses the day-side magnetopause, resulting in enhancements and rearrangements of the complex current systems near the Earth. These current system changes are as well observed as magnetic field fluctuations at ground-level (McPherron, 1995). This is evident in figure 1b in which depletion was seen in H component of the Earth’s magnetic field across all the latitudes, as the geomagnetic storm occurred. Figure 1a: Hourly variations of interplanetary indices and Dst Figure 1b: Hourly variations of H component at high latitude (Baker Lake), mid-latitude (Tucson) and equatorial region (Guam)4.2 Diurnal Variations of Interplanetary Indices, Dst, Z and H.Figures 2a-2c showed the diurnal variations of Bz, solar wind speed and Dst respectively. The plots showed a 31
  • 5. Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol 4, 2012sharp increase in the negative value of Bz just before the storm and solar wind value increases positivelybefore the storm. Figures 3a-3c is the plots of diurnal variations of H over April 2010 and it showed thevalues of H for each day of the month. There is a sharp decrease in the values of H across all the latitudesduring the geomagnetic storm. Geomagnetic storms occur during longer periods of steady southward IMFand are characterised with a global decrease of the horizontal geomagnetic field component at middle andlow latitudes. For example, (Gonzalez et al., 1994) observed that at the ground, the main phase and recoveryphases of a storm are characterized by a decrease in horizontal magnetic field intensity and then slow returnto baseline. 32
  • 6. Advances in Physics Theories and Applications www.iiste.orgISSN 2224-719X (Paper) ISSN 2225-0638 (Online)Vol 4, 2012 33
  • 7. Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol 4, 20124.3 The Storm Phase Figure 5: The sudden commencement, main phase and recovery phase of April 4th -8th 2010 stormFrom figure 5, the southward component of the interplanetary magnetic field (IMF), Bz , increases sharply tothe magnitude of 11.4nT at 1100UT from 0.1nT at 1000UT on April 5. Immediately the sudden increase in,Bz a sharp increase was seen in the magnitude of solar wind speed which shows the sudden commencementof the storm at -53nT on April 5. This result is in agreement with (Burton et al, 1975) observation that geoeffectiveness of solar wind depends upon the speed and embedded southward magnetic field. And, (Yadav,2005) observed that 70% of GMSs are associated with southward component of IMF, Bz ,alone. Furthermore,it is observed that the product of V and B directly modulates the geomagnetic activity.On April 6, at 0700UT the storm magnitude increased to -67nT which shows the main-phase of the storm andthis increased to -73nT at 1400UT of April 6. The recovery phase occurred during the period of negativefield. However, immediately the storm of April 6 has recovered, an increase was seen again in the value of Bzat 0700UT on April 7 which shows another storm but the magnitude was low (-50nT) compared to theformer.5.0 ConclusionsThe daily and hourly averages of the interplanetary indices with Dst showed a sharp increase in themagnitude of, Bz which is at 12hours before the sudden commencement of the storm. The solar wind speedincreases suddenly prior to the main phase. The recovery phase is seen as, Bz drops and solar wind decrease.There is a sharp decrease in the magnitude of H which cut across all the latitudes. The main phase andrecovery phases are characterized by a decrease in horizontal magnetic field intensity and then slow return tobaseline. The magnitude of the vertical component, Z, increases across all the latitudes during the storm.Acknowledgements. The results of the horizontal and vertical component of the Earth’s magnetic fieldpresented in this paper rely on data collected at magnetic observatories. We thank the national institutes that 34
  • 8. Advances in Physics Theories and Applications www.iiste.org ISSN 2224-719X (Paper) ISSN 2225-0638 (Online) Vol 4, 2012support them and INTERMAGNET for promoting high standards of magnetic observatory practice(www.intermagnet.org). We also thank the OMNIWEB (omniweb.gsfc.nasa.gov/ow.html) for theinterplanetary indices data.ReferencesBurton et al, 1975, ‘An empirical relationship between Interplanetary Conditions and Dst’J.Geophys. Res., vol 80, No 31.Chandra, H., Sinha, H. S. S and Rastogi, R. G. (2000), Equatorial Electrojet studies from rocket and groundmeasurements, Earth Planets Space, Vol. 52, pp 111-120Foster, J. C., D. H. Fairfield, K. W. Ogilvie, and T. J. Rosenberg. (1971),’ Relationship of interplanetaryparameters and occurrence of magnetospheric substorms’, J. Geophys. Res., 76, 6971Gonzalez, W.D., et al., (1994), What is a geomagnetic storm? Journal of Geophysical Research 99,5771-5792.Ganon and Love (2010), USGS 1-min Dst index, J. Atmospheric and Solar-Terrestrial Physics 73 (2011)323–334McPherron, R.L. (1995), Magnetospheric dynamics. In: Russell, C.T., Kivelson, M.G. (Eds.), Introduction toSpace Physics. Cambridge University Press, Cambridge, UK, pp. 400–458.Russel et al., 1974, ‘On the causes of geomagnetic storms’, J.Geophys. Res, 79, 1105.Rostoker and Falthammar (1967), Relationship between changes in the interplanetary magnetic filed andvariations in the magnetic field at the Earth’s surface, J.Geophys. Res., 72(23), 5853.Rabiu, A.B. (2000), Geomagnetic variations at middle latitude, PhD thesis submitted to the department ofPhysics and Astronomy, Univ. of Nsuka, Nigeria.Rabiu, A. B., Mamukuyomi, A. I. and Joshua, E. O., (2007), Variability of equatorial ionosphere inferredfrom geomagnetic field measurements. Bulletin of the Astronomical Society of India, Vol. 35, pp 607-618Yadav, M.P. (2005), Comparative study of SWP and IMF parameters with DST ≤ - 100 nT in associationwith large geomagnetic storms. 29th International Cosmic Ray Conference Pune (2005) 00,101-104 35
  • 9. International Journals Call for PaperThe IISTE, a U.S. publisher, is currently hosting the academic journals listed below. The peer review process of the following journalsusually takes LESS THAN 14 business days and IISTE usually publishes a qualified article within 30 days. Authors shouldsend their full paper to the following email address. More information can be found in the IISTE website : www.iiste.orgBusiness, Economics, Finance and Management PAPER SUBMISSION EMAILEuropean Journal of Business and Management EJBM@iiste.orgResearch Journal of Finance and Accounting RJFA@iiste.orgJournal of Economics and Sustainable Development JESD@iiste.orgInformation and Knowledge Management IKM@iiste.orgDeveloping Country Studies DCS@iiste.orgIndustrial Engineering Letters IEL@iiste.orgPhysical Sciences, Mathematics and Chemistry PAPER SUBMISSION EMAILJournal of Natural Sciences Research JNSR@iiste.orgChemistry and Materials Research CMR@iiste.orgMathematical Theory and Modeling MTM@iiste.orgAdvances in Physics Theories and Applications APTA@iiste.orgChemical and Process Engineering Research CPER@iiste.orgEngineering, Technology and Systems PAPER SUBMISSION EMAILComputer Engineering and Intelligent Systems CEIS@iiste.orgInnovative Systems Design and Engineering ISDE@iiste.orgJournal of Energy Technologies and Policy JETP@iiste.orgInformation and Knowledge Management IKM@iiste.orgControl Theory and Informatics CTI@iiste.orgJournal of Information Engineering and Applications JIEA@iiste.orgIndustrial Engineering Letters IEL@iiste.orgNetwork and Complex Systems NCS@iiste.orgEnvironment, Civil, Materials Sciences PAPER SUBMISSION EMAILJournal of Environment and Earth Science JEES@iiste.orgCivil and Environmental Research CER@iiste.orgJournal of Natural Sciences Research JNSR@iiste.orgCivil and Environmental Research CER@iiste.orgLife Science, Food and Medical Sciences PAPER SUBMISSION EMAILJournal of Natural Sciences Research JNSR@iiste.orgJournal of Biology, Agriculture and Healthcare JBAH@iiste.orgFood Science and Quality Management FSQM@iiste.orgChemistry and Materials Research CMR@iiste.orgEducation, and other Social Sciences PAPER SUBMISSION EMAILJournal of Education and Practice JEP@iiste.orgJournal of Law, Policy and Globalization JLPG@iiste.org Global knowledge sharing:New Media and Mass Communication NMMC@iiste.org EBSCO, Index Copernicus, UlrichsJournal of Energy Technologies and Policy JETP@iiste.org Periodicals Directory, JournalTOCS, PKPHistorical Research Letter HRL@iiste.org Open Archives Harvester, Bielefeld Academic Search Engine, ElektronischePublic Policy and Administration Research PPAR@iiste.org Zeitschriftenbibliothek EZB, Open J-Gate,International Affairs and Global Strategy IAGS@iiste.org OCLC WorldCat, Universe Digtial Library ,Research on Humanities and Social Sciences RHSS@iiste.org NewJour, Google Scholar.Developing Country Studies DCS@iiste.org IISTE is member of CrossRef. All journalsArts and Design Studies ADS@iiste.org have high IC Impact Factor Values (ICV).