ESS 261 Topics in Magnetospheric Physics Spring 2008 Forecasting Space Weather

Syllabus March 31 Why Study Space Weather? ® April 7 Humans and Space Weather ® April 9 Basics of Magnetic Storms ® April 11 (F) CMEs ® April 14 CIRs April 16 Differences between CME and CIR Storms April 23 Space Weather Forecast Models (Costello Geomagnetic Activity Index, Relativistic Electron Forecast, Wang Sheeley, Total Electron Content model) April 28 Space Weather Forecast Models continued April 30 Introduction to simulation codes ® May 5 Introduction to MHD models ® May 7 Introduction to CCMC ® May 12 The importance of accurate solar wind ® May 14 ENLIL (solar wind model) ® May 23 (F) Magnetospheric models ® May 28 SEPs at Earth ® May 30 (F) Modeling from the Sun to the Earth June 2 Modeling a CME June 4 Modeling a CME at Earth

Grading Each student will be required to make a presentation on a topic related to space weather. – 50% Each student will be required to participate in a group attempt to use existing simulation codes to model a space weather event.- 50%

Lecture 1 Why Study Space Weather? Society has grown very dependent on systems adversely affected by space weather phenomena.

A few of the agencies and industries that rely on space weather services today: U.S. power grid infrastructure Commercial airline industry Dep. of Transportation ( GPS) NASA human space flight activities Satellite launch and operations DoD Operations DOE Nuclear Reg Comm Schlumberger NY/PJM Grid Ball Loral NESDIS/SOCC Digital Globe Boeing Lockheed Aerospace Echostar NASA Space Command ISS Astronauts FAA American United Airlines Northwest Continental Growth of Space Weather Customers Sunspot Cycles Commercial Space Transportation Airline Polar Flights Microchip technology Precision Guided Munitions Cell phones Atomic Clock Satellite Operations Carbon Dating experiments GPS Navigation Ozone Measurements Aircraft Radiation Hazard Commercial TV Relays Communications Satellite Orientation Spacecraft Charging Satellite Reconnaissance & Remote Sensing Instrument Damage Geophysical Exploration. Pipeline Operations Anti-Submarine Detection Satellite Power Arrays Power Distribution Long-Range Telephone Systems Radiation Hazards to Astronauts Interplanetary Satellite experiments VLF Navigation Systems (OMEGA, LORAN) Over the Horizon Radar Solar-Terres. Research & Applic. Satellites Research & Operations Requirements Satellite Orbit Prediction Solar Balloon & Rocket experiments Ionospheric Rocket experiments Radar Short-wave Radio Propagation

Cartoon of CME Hitting the Earth

Space Environment Effects: Surface Charging

Spacecraft charging is a variation of the electrostatic potential of the spacecraft surface with respect to the surrounding plasma. The resulting discharges can: –Cause spurious electronic switching –Breakdown vehicle thermal coatings. –Degrade amplifiers and solar cells –Degrade optical sensors. Photoionization frees electrons from the spacecraft and it develops a positive charge. –Electrons may form a negative cloud near the spacecraft. –If the entire surface was a homogeneous conductor this would not be a problem but this isn’t the case. –Differential charging of the sunlit surface with respect to the dark surface. Electrons with energies of a few keV can penetrate the skin of the spacecraft and charge it negatively.

SCATHA (Reagan et al., 1981) Surface Charging: SCATHA Satellite Observations.

Space Environment Effects: Deep Dialectric Charging

Electrons with energies between 2 and 10 MeV have enough energy to get deep into satellite surfaces. The excess charge spreads out evenly on conducting surfaces but the charge accumulates on dielectric surfaces resulting in potential differences between different parts of the satellite. Eventually static discharges will occur. This can happen on electron circuitry. Plot shows count rate of 3 MeV electrons versus time. Arrows show times when the spacecraft star tracker had anomalies.

3. Influx of electrons increases to levels higher than the leakage rate 2. Electrons slowly leak out of the insulator 1. Electrons bury themselves in the insulator 4. Electrons build up faster than they leak off 5. Discharge (electrical spark) that damages or destroys the material High Energy Electrons: Deep-Dialectric Charging

Surface Damage in a C2 MOS capacitor

Space Environment Effects: Single Event Upsets

Single Event Upsets –Single event upsets are bit flips in digital micro-electronic circuits.  Damage to stored data.  Damage to software.  Stop central processing unit (CPU).  Cause CPU to write over critical data tables.  Create faulty commands. –Caused by high energy ions ionizing silicon electronics.  Galactic cosmic rays.  SEPs  Radiation belts. Additional hazards that affect spacecraft systems. –Variable atmospheric drag –Enhanced ionospheric ionization –Solar x-ray (SX) and Energetic Particle Events (SEPs). –Relativistic electron events (REE) –Magnetospheric particles and fields.

Background caused by Solar Energetic Particles

Spacecraft operating below a few thousand kilometers encounter a significant number of atmospheric particles during each orbit. Any mechanism that heats the atmosphere will produce density increases above the level heated. –Geomagnetic storms –Changes in solar extreme ultraviolet (EUV) radiation. Heating during magnetic storms –Strong field-aligned currents and enhanced electrojets contribute to atmospheric heating. –Most of the heating is in the auroral zone so polar orbiting satellites experience the greatest effects. Enhanced drag can cause satellites to reenter the atmosphere. –Enhanced drag at perigee will cause the orbit to become more circular and increase the interval with drag. –Even a single density increase will alter all future orbits.

Launches must be postponed during solar particle events Launches for a number of rockets must be postponed if the flux of >50MeV protons exceeds 100 pfu. The proton fluxes interfere with the guidance system.

What would satellite operators do if they had accurate space weather forecasts? Instruments and/or spacecraft turned off or safed Maneuver planning Anomaly assessments Orbit determination accuracy Increased spacecraft and instrument monitoring for health and safety during solar storms

Humans in Space Particle events >30MeV are a concern. Can lead to cancellation of an EVA. 100MeV ions >200pfu and crew will shut off equipment.

Danger to aviation High frequency (3-30MHz) communications problems in polar regions. By 2018 estimated 1.8 million passengers between US and China. HF Communication only

Danger to aviation at lower latitudes The FAA Wide Area Augmentation System (WAAS) is used to navigation at lower latitudes. WAAS uses the GPS satellites.

WAAS altitude errors Ionosphere Disturbances impact vertical error limits, defined by the FAA’s Lateral Navigation Vertical Navigation (LNAV/VNAV) specification to be no more that 50 meters. Commercial aircraft unable to use WAAS for precision approaches. Space weather can cause errors greater than 50 meters.

North America Electric Reliability Corporation (NERC) NERC is the Federal Energy Regulatory Commissions electric reliability coordinator. Organized into a series of regional coordinators. Develops and enforces reliability standards.

Transformer exit lead overheatingTransformer winding failure Transformers destroyed by induced currents. Area affected by blackout.