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Fb2 From the Sun: Auroras, Magnetic Storms, Solar Flares, Cosmic Rays (Special Publications) ePub

by Steven T. Suess,Bruce T. Tsurutani

Category: Astronomy and Space Science
Subcategory: Science books
Author: Steven T. Suess,Bruce T. Tsurutani
ISBN: 0875902928
ISBN13: 978-0875902920
Language: English
Publisher: American Geophysical Union; 1 edition (February 4, 1998)
Pages: 172
Fb2 eBook: 1597 kb
ePub eBook: 1790 kb
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Solar flares, concurrent cosmic ray bursts and subsequent geomagnetic storms

Solar flares, concurrent cosmic ray bursts and subsequent geomagnetic storms. April 1958 · Acta Physica Academiae Scientiarum Hungaricae. On February 13, 1967 at 1746 UT, the brightest flare of that year erupted from the surface of the Sun. Approximately 56 hr later, the sudden commencement of a magnetic storm was recorded by many observatories around the world. Midway between the worldwide sudden commencement and the termination of the magnetic storm, there occurred at Ft.

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From the Sun Auroras, Magnetic Storms, Solar Flares, Cosmic Rays Special Publications.

Steven T. Suess, Bruce T. Tsurutani. The human impact of solar flares and magnetic storms. Published: 1 January 1998. by American Geophysical Union (AGU). in From the Sun: Auroras, Magnetic Storms, Solar Flares, Cosmic Rays. From the Sun: Auroras, Magnetic Storms, Solar Flares, Cosmic Rays; doi:10. From the Sun: Auroras, Magnetic Storms, Solar Flares, Cosmic Rays pp 67-72; doi:10.

Magnetic Storms, Substorms and Geomagnetic Quiet: Solar Cycle Dependences. Nonlinear Plasma Waves (Evolution, Turbulence, Stochastic Particle Acceleration). Plasma Physics (Instabilities and Wave-Particle Interactions). Ionospheric Physics: The Dayside Superfountain Effect, Solar Flare Effects. Sobral, and N. Gopalswamy, Amer.

From the Sun : Auroras, Magnetic Storms, Solar Flares, Cosmic Rays, Paperback by Suess, Steven T. (EDT); Tsurutani, Bruce T. (EDT), ISBN 0875902928, ISBN-13 9780875902920, Brand New, Free P&P in the UK The 16 contributions explain how solar eruptions affect human technology and society, and are intended for the non-specialist. The chapters are modified from articles originally published in Eos Transactions. Annotation c. by Book News, In. Portland, Or. Read full description. See details and exclusions.

Published by the American Geophysical Union as part of the Special Publications Series. From the Sun demystifies auroras, magnetic storms, solar flares, cosmic rays and other displays of Sun-Earth interactions. The authors, all well-known figures in space science, explain how solar eruptions affect human technology and society in articles intended for the nonspecialist and adapted from Eos, Transactions, American Geophysical Union.

org or from used book sellers Whitham D. Reeve.

Sensitive magnetic sensors will experience high noise levels during geomagnetic storms. Joselyn, Jo Ann, The Human Impact of Solar Flares and Magnetic Storms, from From the Sun, Steven T. Suess and Bruce T. Tsurutani, ed. AGU, Washington, . These include sensors to measure motion along crustal faults of the Earth, to guide deep drilling projects, to map subsurface resources, and to chart the ocean floor. The high noise levels interfere with accurate readings.

The long-time series of daily means of cosmic-ray intensity observed by four neutron monitors at different cutoff .

The long-time series of daily means of cosmic-ray intensity observed by four neutron monitors at different cutoff rigidities (Calgary, Climax, Lomnický Štít and Huancayo/Haleakala) were analyzed b. .Jokipii, J. 1998, in S. T. Suess, B. Tsurutani (ed., From the Sun: Auroras, Magnetic storms, Solar flares, Cosmic rays, American Geophysical Union, Washington, p. 12. oogle Scholar. Joshi, . 1999, Solar Phys. 185, 39.

Published by the American Geophysical Union as part of the Special Publications Series.

From the Sun

demystifies auroras, magnetic storms, solar flares, cosmic rays and other displays of Sun-Earth interactions. The authors, all well-known figures in space science, explain how solar eruptions affect human technology and society in articles intended for the nonspecialist and adapted from Eos, Transactions, American Geophysical Union. One of the most appealing features is a comprehensive glossary of the terminology necessary to read almost any volume on Sun-Earth connections.

Comments to eBook From the Sun: Auroras, Magnetic Storms, Solar Flares, Cosmic Rays (Special Publications)
Insanity
Being a collection of essays by writers of varying talent, this book is not what you'd call a page-turner, unless you have a healthy curiosity about sun-earth physics. I found it a very useful introduction to the field, and plan to use it to guide undergraduate research (I'm a physicist with a doctorate, teaching at an institution with an undergraduate physics program.)The authors have avoided the use of equations, and for me that was a drawback, but for undergrads or laymen, it might be helpful. Lots of very interesting physics here.
Gerceytone
For the graduate or other working physicist, in particular astrophysicists and solar physicists, this is an ideal overview with which to become acquainted with space physics as applied to the Sun-Earth interface. This is accomplished via 16 short essays that range from the Aurora and Magnetosphere of Earth, to magnetic storms, the solar wind and solar flares, and also solar irradiance (a key factor in the Sun-climate relationship) and the solar dynamo.

As with most such texts, the problem is usually that the essays themselves may be somewhat uneven in quality, also that the information contained in certain critical chapters (like the one on solar irradiance) may be rendered outdated by pure happenstance. But more on this in a bit.

My own favorite chapters were the ones on the Aurora, by Syun-Ichi Akasofu (a former Ph.D. thesis supervisor of mine at University of Alaska-Fairbanks), The Earth's Magnetosphere by S.W.H. Crowley, Radiation Belts by James A. Van Allen and Solar Flares by David Rust. In each case, the authors effectively encapsulated the prime attributes of their subject in a way that was both comprehensive (given the space allotted), and clear. For example, Crowley's graphic portrayal of magnetic substorms (p. 21) still is useful today, with only a few tweaks.

Meanwhile, S. Peter Gary's treatment of 'Plasma Waves and Instabilities' (pp. 29-34) was somewhat uneven. Maybe part of this is due to sloppy editing, indeed it probably was. For example, if one is going to present lone equations around which to make a case or develop further points, they need to be accurate and not confuse readers. On page 30, for the fundamental plasma frequency of oscillation, we behold:

v_pc = (4pne^2)/ m_e)^1/2

where the source is cited as Chen (1974). That is, 'Introduction to Plasma Physics' by Francis Chen (p. 73 of his textbook). But one easily observes there's a jarring divergence between what Chen presents and what Gary has. (Of course, one can spot this by merely having familiarily with the plasma frequency!) Thus v_pc needs to be replaced by the small Greek omega symbol, and it is not "4p" in the numerator but 4 pi! For a topical, more or less superficial treatment such as presented in this chapter, one could even use the simple approximation form:

f_p = 9000 [n]^1/2

where f_p denotes the 'reduced' plasma frequency or simply omega_p divided by 2 pi.

On p. 31 Gary notes that plasma waves van lose energy "by a mechanism known as Landau damping" but a bit more elaboration might have helped readers. For example, in certain cases of plasma instability, plasma particles' (Maxwellian) velocity distribution (f(v)) acquires a "bump" on the "tail" (higher velocity end of the distribution), consistent with two streams: an unperturbed one f_o(v) and perturbed one (f_eb ) applicable to the electron beam.

In the region where the slope is positive (df(v)/d v > 0) there is a greater number of faster than slower particles so a greater amount of energy is transferred from particles to associated (e.g. Alfven) waves. Since f_eb contains more fast than slow particles a wave is excited, and there is *inverse Landau damping* such that plasma oscillations with v_ph (phase velocity) in the positive gradient region are unstable. The author does note that the "ion acoustic wave is a good example of this (Landau) damping" but it would have been nice to mention the beam instability in conjunction with the reverse side of the coin.

On the top of p. 31, in giving the "characteristic frequency of waves in magnetized plasmas" as the electron frequency, the equation again appears messed up. It's given as:

W_c INT eB/m_e c

where INT is an integral. It ought to have been:

OMEGA_c = eB/ m_e c

Thus, the INT ought to be taken out and replaced by '='. And once more, get rid of the 'W' and use the Greek capital letter Omega. (Though some authors, e.g. like Chen, still retain the use of a common omega, but with subscript c appended).

On the bottom of p. 31, reference is made to "virtually every disturbance of a plasma" corresponding to a non-thermal plasma but no where does one see 'non-thermal" defined. (There is a definition given on p. 164 for a 'Non-thermal distribution' which is said to be 'Non-Maxwellian'). But in general, it wouldn't hurt to note on p. 31 that a non-thermal plasma exhibits electrons at much higher temperature (higher v) with any associated heavy ions at much lower temperature (usually 'cold' plasma conditions).

Moving on to A.D. Richmond's 'The Ionosphere and Upper Atmosphere' (p. 35) one finds a generally well-written, well-presented synopsis with the exception on p. 42, where once again, the sole equation is given. (Perhaps this ought to be a cautionary tale for those seeking to span the two worlds of science populism and rigor to allow equations to naturally enter as they will, and expect more of readers rather than less).

In the sentence preceding the equation we read:

"If E and v are the electric field in the frame moving with the plasma is E + v X B (for a non-relativistic Lorentz transformation) then:

E + v X B ~ 0"

Which makes absolutely no sense at all, so clearly perhaps, this chapter fell victim to poor editing at this point.

The author does go on to note the given equation (actually an approximation by virtue of the '~') means the electric field and plasma velocity are closely linked, but it might have been nice to add that even a minuscule induced voltage arising from, E = -v X B (e.g. due to very small relative motion v) would produce an infinite current j = o E (o = electrical conductivity). The only way one avoids this unrealistic situation is to require the plasma motion in the filament to follow magnetic field lines rather than cut across them, so in this (ideal MHD) case, E + v X B = 0.

Peter Foukal's 'Solar Irradiance Variations and Climate' (p. 103)is a commendable exposition which includes sample results from the ACRIM, or 'Active cavity radiometer irradiance monitor, from the Solar Maximum Mission (SMM), but alas, was published too early to confront the peculiar (early phase spotless) Solar cycle 24! This is important since irradiance has a direct bearing on the issue of climate change and to what degree the Sun is responsible, and especially whether (quantitatively) its irradiance over any one solar cycle or period therein overrides the human-incepted, CO2 -driven, greenhouse effect.

In his lecture at the 40th Meeting of the Solar Physics Division of the American Astronomical Society in June, 2009 ('Solar Irradiance: Recent Results and Future Research Plans') Thomas N. Woods of the University of Colorado dealt with the matter as it pertains to the current cycle, and in particular some recent measurements.

Woods began by noting the assorted recent periods wherein irradiance measurably varied, including: the Medieval maximum, the Sporer minimum (1400s), the Maunder minimum (1600s), the Dalton minimum (1800s). He noted with emphasis that there is no single uniform value to characterize a time interval or period, since the radiance itself can vary hugely on small or local scales. For example, solar flares can propel radiance increases 50 times over normal and thereby affect the irradiance.

On average though, with such violent inputs smoothed out, the Earth's temperature changes by about 0.07 K (kelvin) over a solar cycle. Compare this to the 0.6 K change (increase) in global temperatures over the past 100 years arising from human-caused greenhouse effect. Thus, the human component is over 8.5 times greater.

Even if the solar forcing on climate is enhanced by positive feedbacks, the amplification is usually no more than a factor 2. So that 0.07 K increases become 0.14 K increases. The human component is still more important by a factor 4.2, a point made by Woods when he emphasized that the recent results support the hypothesis that anthropogenic greenhouse gases are the primary contributor. This despite all the politicos, think tanks and yahoos who keep blabbering that climate change arises from "natural cycles" - meaning the Sun is responsible.

In his envisaging of future results and research, Prof. Woods echoed a plaintive cry I've often made: that for really solid and unimpeachable irradiance quantification we need to be able to detect and record the real total luminosity change from minimum to minimum. Other questions we need to have addressed to sleep better at night include: 1) How exactly are changes in the solar magnetic field related to irradiance, 2) What specific end-to -end calibrations are needed to obtain the total solar irradiance per cycle?, 3) How can we account for a nearly 8% difference in irradiance as compared to measurements made in the near infrared?

Foukal does note the "high frequency variation of the irradiance signal" (p. 104) but minus the early jolting data from cycle 24 it seems somehow incomplete, and unconvincing.

This leads us to the consideration of the putative solar dynamo (David Hathaway, p. 113). Here, I commend Hathaway for not only giving an articulate account but also not shying away from presenting the partial differential equations (e.g. for the alpha-effect and omega-effect dynamos). If the book is reprinted, this is what one would like to see more of.

At the end of the essay, p. 118, Hathaway summarizes a number of the problems with the existing alpha-omega (Babcock-Leighton) type dynamo, which is good - considering that solar cycle 24 with its incredibly delayed sunspots showed the existing problems in searing, stark contrast.

What we do know is that the much delayed spot behavior of cycle 24 appears to pose more serious questions than originally believed for solar dynamo theory. This is the theory that every 11 years or so, magnetic fields on the Sun attain a high torsional component which causes them to "twist" up and also move from more northerly to more southerly solar latitudes where most active regions (ARs) form. Typically, this is around 22-23 heliographic degrees.

As pointed out at the same 2009 SPD meeting, the torsional oscillation flow for the early part of the cycle hovered near heliographic latitude 33 degrees, nearly 10 degrees off! Even moving at about 7 Mm (mega-meters or 10^6 meters) a year southward, this would take over 2 years to reach a latitude of 23 degrees, where large active regions (and spots!) ought to form. This may well be connected with Hathaway's last problem facing dynamo theory (p. 121) wherein "magnetic diffusion is needed for magnetic fields to reconnect and form new topologies". Perhaps also, playing a role in these new topologies, is the magnetic helicity with respect to the Sun's northern and Southern hemispheres. We generally posit "right handed" helicity for the N-hemisphere, and left-handed for the Southern, but can we be certain this invariably holds?

To show how amiss we currently are, one paper presented at the same SPD conference I attended displayed beautiful, multi-layered cross sectional views of the solar meriodonal flows in full color. But when the presenter was asked to show the actual observational data that supported it, nearly ninety-five percent of the colored lines and contours vanished! Clearly, there's a lot of unwarranted extrapolation.

For their part, the torsional oscillations tend to occur about 1000 kilometers below the Sun's surface (photosphere) but we have few instruments that can actually probe that deeply. One refrain one heard over and over in terms of supporting dynamo theory was: 'We need more money!'

Well, let us hope there are no more serious budget cuts in that respect, given the extent to which the Sun affects all of our lives, a fact made boldly evident in the 16 essays in this book - irrespective of the occasional foibles and lax editing!
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