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UNH PHYS 954 - Introduction

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Introduction of courseScope:The class covers the energetic radiation and the wind from the sunE&M, Fluid Mechanics, Thermodynamics, Statistical Physics1) Magnetohydrodynamics:Viewgraph Heliosphere - Interstellar Gas2) Particle dynamics:Historic overview (after articles by Cliver, EOS 75, p. 569 and 609, 1994)Viewgraph Sunspots - Magnetic Field DisturbancesChapman alpha particles from the sunPhysics 954, Solar Wind and Cosmic Rays 0. IntroductionE. Möbius0. IntroductionIn "Solar Wind and Cosmic Rays" we will talk about Physics in the heliosphere. Here many processes are accessible to in-situ measurements that are very important for astrophysical problems at distant stars. This will be an introduction to ongoing studies at the Space Science Center of UNH, in the Solar Terrestrial Theory Group and in the Space Plasma Physics Group. We will not only touch the physical background of the phenomena, but also talk about the instrumentation and the measurements necessary to reveal these phenomena. Viewgraph (Heliosphere)Right now we have an exciting time, because several spacecraft are on their way out of the heliosphere, one spacecraft scans regions over the poles of the sun. In addition, we have several highly sophisticated spacecraft in the near Earth environment, which study the sun, the interplanetary medium and the impact on the Earth’s magnetosphere. We have instruments on several of these spacecraft to study the phenomena that I am going to talk about.Introduction of course- grading- homework- class presentation by students- term paper on subject of class presentationScope:The class covers the energetic radiation and the wind from the sunWe need the following as pre-requisites: E&M, Fluid Mechanics, Thermodynamics, Statistical PhysicsPlasma Physics (if taken parallel, o.k.)The topics covered in this course fall basically into two categories:MagnetohydrodynamicsParticle dynamics according to the physical description:1) Magnetohydrodynamics:- solar wind- interplanetary magnetic field- obstacles to the wind- shocks -> particle acceleration- magnetic reconnection -> particle accelerationViewgraph Heliosphere - Interstellar Gas1/14/19 1Physics 954, Solar Wind and Cosmic Rays 0. IntroductionE. Möbius2) Particle dynamics:- interstellar gas and pickup ions- particle transport- energetic particle populations and acceleration- different populations of cosmic rays (as far as we get)In addition, we will cover the instruments needed to observe the phenomena under investigation in separate instrumentation sections that may move around in the course, depending on progress.Historic overview (after articles by Cliver, EOS 75, p. 569 and 609, 1994)See also: Kallenrode, p. 4 - 8The solar corona was known from observations during eclipses.1722: In England, Graham devised sensitive compass, which could see geomagnetic field disturbances1740: In Sweden, Celsius and his student Hiorter noted that aurorae were accompanied by disturbances of the magnetic needle. In collaboration with Graham they saw that this was not local.1830: In Germany, Gauss started a systematic study of these disturbances. The Göttingen Magnetic Union, a coalition of magnetic observatories, was founded. This was found useful for navigation, and the British Colonial Observatories were set up all over the globe(Toronto, Hobart - Tasmania, St. Helena) under the direction of (Colonel) Edward Sabine.At the same time continuous observations of solar activity really started.1826: In Germany, Heinrich Schwabe, a pharmacist, started making sun spot counts. He published the periodic behavior in 1838.1852: Sabine noted that the geomagnetic activity tracked the sun spot cycle.Viewgraph Sunspots - Magnetic Field DisturbancesThis can be traced as the origin of solar-terrestrial physics and in hindsight the first indication towards solar particles influencing the Earth.Herschel in a letter to Faraday: "If all this be not premature we stand on the verge of a vast cosmical discovery such as nothing hitherto can compare with."1859: Carrington observed a solar flare, when looking for sunspots. He noted a magnetic disturbance simultaneously and a large magnetic storm 18 hours later. He could have found the solar cosmic rays (simultaneous reaction) and the solar wind (delayed reaction). He did not draw physical conclusions from this. Simply the information was not conclusive at that time.Thomson and Kelvin showed that solar magnetic fields had to be too strong to cause the effects.1/14/19 2Physics 954, Solar Wind and Cosmic Rays 0. IntroductionE. Möbius1868 -71: Janssen, Lockyer and Secchi observed prominences, quiet and active ones. The active ones eventually moved with more than the sun's escape velocity. -> solar corpuscular hypothesisAt the same time Airy showed that transient currents outside the Earth caused the magnetic disturbances.1892: The corpuscular hypothesis is strengthened by Maunder, Birkeland, Chapman and Ferraro.Maunder noted that three strong storms were associated with 3 outstanding sunspot groups.Sabine and Ellis found that the disturbances occurred within minutes all over the globe and thus concluded that they had to come from outside. Around the turn of the century Chree found the 27 day variations concurrent to the sun's rotation, another clue for the solar origin.Birkeland made his famous "Terella" experiments to demonstrate what charged particles could doto a magnetic field.Chapman alpha particles from the sunLindemann plasma from the sun -> Chapman: revision of model 1931Just fell short of solar windWhereas the evidence on the solar wind grew slowly over the last century, cosmic rays are really achild of this century. (Article in Astronomy 2000!)1912: Hess detects radiation in balloon flights1927: when the influence of the Earth's magnetic field is found it is accepted that this radiation is of extraterrestrial origin and charged particles.1940: Radiation is mostly protons1948: Heavier nuclei are found; up to here all studies were carried out from balloons. We are talking about particles with more than several hundred MeV energy here. Most of the particle populations, which we will be talking about in this class, became accessible only with spaceflight!Examples from “Bastille Day Flare”. Our technical society has become vulnerable to effects from solar wind and radiation. NASA is working on this within the “Living with a Star” program.1/14/19

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