EMİNE CEREN KALAFATOĞLU EYİGÜLER

Transcription

1 EMİNE CEREN KALAFATOĞLU EYİGÜLER SPACE ENVIRONMENT UZB411E FALL ROOM: 322 / THIRD FLOOR UPPER ATMOSPHERE AND SPACE WEATHER LAB OFFICE HOURS: EVERY TUESDAY AND WEDNESDAY BETWEEN FOR OTHER TIMES CONTACT TO GET AN APPOINTMENT [email protected] Web site:

2 Space Weather: Geomagnetic Storms, Magnetic Substorms Signatures, Consequences & Forecast : An overall Introduction Emine Ceren Kalafatoğlu Eyigüler Istanbul Technical University Faculty of Aeronautics and Astronautics

3 Today s Menu Space Weather and the Near Earth Space Environment What is a geomagnetic storm? What is a substorm? Consequences of geomagnetic storms Observational Signatures Real-Time Forecast - Organisations ISWA September 5, 2005 CME [1]

4 Space Weather Definition Conditions on the Sun and in the solar wind, magnetosphere, ionosphere, and thermosphere that can influence the performance and reliability of space-borne and ground-based technological systems and that can affect human life and health. (definition used by the U.S. National Space Weather Plan)

5 Steps to Space Weather Forecasting & Minimizing the Influence 1. Observe the Sun and the solar wind 1. Solar activity 2. Potential active regions 2. Detect the activity beginning and properties 3. Find the time of arrival (X=V.t) to the point of interest 4. Predict and assess the consequences: Estimate the impact on 1. Spacecraft (LEO) 2. Systems on Earth (city grid, pipelines) 3. Astronauts in space, polar orbit flight crew

6 PART 1- OBSERVE THE SUN Why? Solar activity dominates the space weather.

7 How do we observe the Sun and the solar wind? Solar surface: Satellites with imagers Imagers: SOHO, STEREO, HINODE, TRACE, SDO, ULYSSES Imagers on Earth Ground based telescopes The solar wind: WIND (halo orbit around the L1 Lagrange point) Advanced Composition Explorer (has enough propellant on board to maintain an orbit at L1 until ~2024) [7, 8]

8

9

10 What to keep in mind? The Sun is Magnetic

11 The Sun Solar Minimum Solar Maximum Magnetic field lines stretch out of the solar surface during solar maximum and solar minimum but the configuration is different. Images are generated by CISM_DX using previous model run results for solar minimum and maximum conditions: Center for Integrated Space Weather Modeling Summer School Boston University

12 Sources of Activity Active regions ( X-ray and ultraviolet images), Sunspots (Visible and HMI) Filaments and Prominences Coronal Holes [1, 3, 4]

13 Active Regions and Sunspots Source regions of solar flares and CMEs

14 Filaments and Prominences Sources of CMEs Disk view/ Facing the imager = Filament Side view/ On the limb = Prominence

15 Coronal Holes Region of open field lines with rarefied solar wind density and high speed particles Source of the High Speed Streams

16 -USEFUL CONCEPTS- HOW DO THE SUN AFFECT US? WHAT IS THE THEORY? 1) FROZEN IN FLUX THEOREM

17 Why are we interested in the solar magnetic field, active regions and the stretched magnetic field lines? Frozen-in-Flux Theorem which states Two fluid elements are always connected by a magnetic field line if they were connected at one time by a field line Koskinen H., Introduction to Plasma Physics lecture notes, 2008.

18 Application to the Sun and Planets Relationship

19 Sun-Planet Connection

20 The Space Environment REGIONS SOLAR WIND Average solar wind values: CURRENT SYSTEMS Vsw= 400 km/sec Density= 3 to 6 atoms per cc Temperature= K Dynamic Pressure= 1.2 npa [12]

21 PART 2- DETECT THE ACTIVITY BEGINNING and PROPERTIES Why? PART 3- TO PREDICT WHEN THE ACTIVITY WILL AFFECT EARTH and ITS STRENGTH

22 What can come from the Sun?- Solar Flares Solar flares emit huge bursts of electromagnetic radiation, including X-rays, ultraviolet radiation, visible light, and radio waves. The energy emitted by a solar flare is more than a million times greater than the energy from a volcanic explosion on Earth! X-rays &EUV arrive in 8 min. Close look: 1998, July 14 Flare [5] Rearranging of the solar magnetic field November 2003 solar flare [2]

23 Flare Classification

24 What can come from the Sun?- Coronal Mass Ejections (CME) High density, variable speed plasma cloud coming from the Sun 18 August CME magnetic reconfiguration and release of a plasma cloud.

25 CME Classification

26 What can come from the Sun?- High speed streams Source: coronal holes days period; with the rotation of Sun. Create consequtive substorms. 2. Common during solar minimum because of the comparatively stable current sheet, and long duration coronal holes. 3. Increased V, lower number density with respect to CMEs. [5]

27 So what happens? CME Arrival to Earth Dayside Reconnection Nightside reconnection Energy transfer to the atmosphere Formation of aurora

28 PART 4- ASSESSMENT AND PREDICTION OF THE CONSEQUENCES

29 Going Back to the History The Carrington Sunspot: First person to suggest Sun effects the Earth directly. Had seen a white light flare and proposed the linkage between the following magnetic activity on Earth.

30 ADIATION DOSAGE FOR ASTRONAUTS & AIRLINE PASSENGERS RADIATION BELTS GET MORE POPULATED: SPACECRAFT TECHNOLOGY TAIL FLOWS, RECONNECTION & COMPRESSION ON THE DAY SIDE PARTICLE PRECIPITATION THERMOSPHERIC CIRCULATION REVERSAL HEATING OF THE UPPER ATMOSPHERE INCREASED DRAG ON SATELLITES RADIO COMMUNICATION & HF BLOCK OUT GEOMAGNETICALLY INDUCED CURRENTS HIGH VOLTAGE ON THE ELECTRIC GRID

31 29 October 2003 Halloween Solar Storm Halloween Storm spawned aurorae that were seen over most of North America. Extensive satellite problems were reported, including the loss of the $450 million Midori-2 research satellite. The Solar and Heliospheric Observatory (SOHO) satellite, a collaboration between NASA and the European Space Agency (ESA), failed temporarily. NASA's Advanced Composition Explorer (ACE) satellite experienced damage, and instruments aboard many spacecraft had to be shut down temporarily. Power outage in Sweden for about an hour Highly publicized in the news media. A huge solar storm has impacted the Earth, just over 19 hours after leaving the sun. This is one of the fastest solar storm in historic times, only beaten by the perfect solar storm in 1859 which spent an estimated 17 hours in transit. A few days later on November 4, 2003 one of the most powerful x-ray flares ever detected, swamped the sensors of dozens of satellites, causing satellite operations anomalies.but no aurora. Astronauts hid deep within the body of the International Space Station, but still reported radiation effects and ocular 'shooting stars'

32 USEFUL CONCEPTS 2) MAGNETIC RECONNECTION Way of transferring the particles from one field line to another: Leads to 1. Reconfiguration of the magnetic field 2. Particle and energy transfer 3. Break down of the Frozen in flux theorem

33 Magnetic reconnection leading to a geomagnetic storm/magnetic substorm

34 HOW TO DETERMINE THE STRENGTH OF A GEOMAGNETIC STORM?

35 GEOEFFECTIVENESS The ability of InterPlanetary magnetic structures in causing geomagnetic storms is referred to as geoeffectiveness, it can be measured using one of the several indices. CLOSELY RELATED TO IMF DIRECTION. Recall reconnection from the flare formation over the active regions on the Sun (Lect2) This time reconnection is at the magnetopause and the magnetotail regions of the Earth s magnetosphere. NECESSITY: SOUTHWARD IMF-OPPOSITE DIRECTION TO EARTH S NORTHWARD MF [17, 18]

36 INDICES What is an index? A single parameter that provides a measure of the state of the system USAGE in MAGNETOSPHERIC STUDIES: To determine the level of activity Frequently used indices Ap, Kp Dst AE: Auroral Electrojet [9, 10]

37 K index and Kp index Kennziffer index: Obtained from the amplitude of largest variation in either of the horizontal components of the magnetic field in 3 Hour interval. Kp index is the planetary range index [13]. Correlation with the Interplanetary Magnetic Field and daily averages of solar wind velocity [14]. 3 hour values Average of 13 subauroral stations measuring the two horizontal field components and calculating the K index [15]. K can vary from 0 to 9, and it has 3 subdigits: +, -.

38 Kp, Aurora Prediction & Storm Strength Kpmax Classification 9 Extreme 9>Kp 8 Severe 8>Kp 7 Strong 7>Kp 6 Moderate 6>Kp 5 Minor Example KP values: KP IS NEVER NEGATIVE!

39 Dst : Disturbance Storm Time Index Ring current index; ring current magnetic field and its total energy. Westward ring current reduction in terrestrial magnetic field Magnetic perturbations in northward horizontal H component at 4 low-latitude observatories is calculated. Uncertanities come from other magnetospheric contributions than the ring current; like magnetopause current which is controlled by P dyn

40 Dst Dst is significant for geomagnetic storms. It doesn t react to substorms. Storm phases can be defined using this index. Dst -100nT -50nT Dst <100nT -30nT Dst < -50nT strongly geoeffective moderately geoeffective weakly geoeffective Sudden Commencement Main Phase Recovery Phase

41 Storm Classification according to Dst

42 [16] AE: Auroral Electrojet or Auroral Envelope AL: Westward Electrojet AU: Eastward Electrojet show the changes in ionospheric conductance and electrical currents. Calculated using the magnetic field disturbances at the auroral stations Total horizontal flow= AE = AU-AL SIGNIFICANT FOR SUBSTORMS Disadvantage: Aurorae may be in high altitudes or too low altitudes so that the correct estimate cannot be done.

43 AE during quiet and disturbed intervals AE>1000 nt Strong Substorms 1000 nt>ae>500 nt Moderate Substorms

44 Geomagnetic Storm Signatures IMF Bz Negative!! means IMF direction is southward: RECONNECTION! ENERGY IS TRANSFERRED TO EARTH S MAGNETOSPHERE MORE EFFICIENTLY! Strong AE (AE=AU-AL) Increasing DST

45 AVERAGE SOLAR WIND CONDITIONS CME INFLUENCE: COMPRESSION DUE TO THE INCREASED DYNAMIC PRESSURE OF THE SOLAR WIND

46 CME & Dst HALO CME means that the CME is coming towards the observer. SCORE CME typification system: S-type: CMEs with speeds less than 500 km/s C-type: Common km/s O-type: Occasional km/s R-type: Rare km/s ER-type: Extremely Rare >3000 km/s

47 HSS & Dst Coronal Hole: Source Region of HSS

48 Sorting out storms and subtorms STORMS Last more than a day Severe events that may lead to technological hazards, interrupt telecommunication and radio signals. May cause the loss of some satellites Both dayside and nightside reconnection Whole magnetosphere is affected Aurorae may expand down to mid-latitudes Negative Dst values smaller than -40 nt are observed SUBTORMS Lasts for several hours Nightside disturbance Most sensed with AE index, Dst doesn t decrease much ( Dst > -40 nt) Generally aurora at high latitudes Useful in studying the physics

49 Magnetosphere During a Major Substorm

50 Aurora and Magnetospheric Environment [5]

51 ENERGY PARTITIONING Solar wind energy input= Ring current (magnetosphere) + electron precipitation (ionosphere) + Joule heating (ionosphere) + Plasmoid energy (magnetosphere: magnetotail)

52 April 6, 2000 Case Energy deposition the the upper atmosphere Hemispheric power signifies the electron precipitation to the upper atmosphere. As seen in the graph, when electron precipitation enhances, aurorae get brighter, and this happens when there is southward IMF Bz pointing out the enhanced reconnection. 52

53 An Example of the Interaction between I-T Neutral Density Increase Height Integrated Joule Heating Enhancement Kalafatoglu E.C., Part of the project carried out for TUBITAK in collaboration with the CCMC, 2014-ongoing study

54 Investigation Methods Ground and satellite combined view Ground measurements: Changes in the Earth s magnetic field, all sky camera images of aurorae, Satellite Measurements: Variations of solar wind plasma, magnetospheric plasma (number density, solar wind velocity, beta parameter, temperature), interplanetary magnetic field components (GSM Bx, By Bz), Earth s magnetic field components Ionospheric Measurements by Incoherent and Coherent Scatter Radars (SuperDARN, EISCAT) Ionospheric drift Density irregularities Polar cap potential, electric field are derived. Models: Simulating the conditions-mhd: Solar models (ENLIL, etc.), Magnetospheric models (BATSRUS, OPENGGCM, GUMICS-4, etc.), Ionospheric models (TIEGCM, IRI, etc.)

55 Special Mission-THEMIS THEMIS will be very useful for your term project!

56 Radars- SuperDARN

57 All Sky Cameras

58 Magnetometers and Electrometers Magnetometer sensor (Zhang et al. 2007, MAG: The Fluxgate Magnetometer of Venus Express, ESA-SP 1295)

59 Space Weather Forecast: An example from US Official forecast issued by NOAA- SWPC (National Oceanic and Atmospheric Administration- Space Weather Prediction Center) old link: renewed web page: Supporting Organisations: NASA-SWRC under the Space Weather Laboratory- Community Coordinated Modeling Center (CCMC) (National Aeronautics and Space Administration- Space Weather Research Center) Validation and dissemination of space weather models Forecast for NASA Robotic Missions

60 Space Weather Forecast: State-of- the-art models ASSA, MSFC MAG4, Solar Flare Monitor for solar activity and flare probability ENLIL (Sumerian god of the wind) for the solar wind & CMEs Space Weather Modeling Framework Model (University of Michigan) SWMF/BATSRUS for the magnetosphere CTIPe, GITM, TIEGCM for the ionospherethermosphere

61 Space Weather Forecast: ISWA- Integrated Space Weather Analysis Cygnets for observation and model output Heliosphere, Magnetosphere, Ionosphere, Planetary/Spacecraft Example layouts:

62 1)WHERE WILL THE CME HEAD TO: ITS DIRECTION

63 2) WHEN WILL THE CME ARRIVE

64 3) WHAT DO WE FORECAST AT EARTH? CME parameters at the Earth 1. B- Interplanetary magnetic field magnitude 2. V- Speed of the CME 3. N- Density of the CME 4. T- Temperature of the CME To find out the CME impact due to its dynamic pressure

65 4) HOW TO PREDICT THE IMPACT? We don t have methods to predict the direction of the IMF at Earth yet. So the models are run for different impact angles Result: Probabilistic KP distribution

66 Conclusion Source is the Sun (active regions, sunspots, coronal holes) We study because of the effects on Near-Earth Environment (and for science!) The amount of energy transported to Earth s atmosphere, and to the environment Radiation Dosage for astronauts Communication and technology related concerns Effects on satellites in LEO due to the atmospheric drag Studies are done getting use of ground-based instruments and instruments on satellites Aim is to be able to predict the solar conditions like daily weather and to understand the physics

67 Thank you! Any questions?

68 References and Image Credits Most of the information on space weather forecast is taken from ISWA which is a product of NASA-Community Coordinated Modeling Center. We appreciate their support regarding the matter. [1] [2] [3] [4] [5] [6] video.google.com [7] [8] [9] Boston University, CISM Summer School, 2009 Lecture notes, Geomagnetic Indices and Space Weather Models, [10] [11] [12] Magnetosphere and the current systems(russell, The Solar Wind Interaction with the Earth s Magnetosphere: A Tutorial, 2006 [13] ntro.html [14] McPherron, Geomagnetism. [15] pb2/pb23/niemegk/kp_index/kp.html [16] Space Physics Text Book, [17] Gopalswamy [18] [19]