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# Space Plasma Physics - Science topic

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Questions related to Space Plasma Physics

Generally, the IV characteristics of Langmuir probes are defined for unmagnetized plasma. How to estimate the electron temperature and plasma density let's say if there is some axial field inside the plasma source(50-100G).

1. Should different kinds of probes be used for measuring in such situations? (Shielded probes).

2. Or the IV traces obtained should be corrected by using some theory?

Thanks in advance

Bharat

In case of electron plasma waves we consider adiabatic compression and take gamma equal to 3 [using equation (2+N)/N]. what do we mean by adiabatic compression here?I mean physical significance.

and in case of ion waves we take gamma equal to 1. here we consider isothermal phenomena.

Please explain this in detail.

with kind regards,

purvi

I have read somewhere that

1. if the time scales of the phenomena to be observed are larger than the times scales of plasma oscillation and

2. spatial length scales are larger than the debye length than fluid theory is applied.

I couldnt understand the second condition, means what is the significance of wavelength of launched wave greater or lower than the debye length

please explain if anybody can ...

thanks in advance

when we study plasma waves (plasma oscillations, electron waves and ion waves) we study perturbation in density, velocity and electric field and use momentum, continuity and poison equation to start with.

after introducing perturbation in each quantity we do linerization of non-linear (or higher order terms).

Please explain why is it necessary at all to do it? what if we do not linearlize the quantity ?

Thank you in advance,

Purvi Dave

When solar flare passes through earth's magnetic field its magnetic field line break and reconnect after 15 minute releasing tremendous amount of energy. Is it possible to break magnetic lines of force by some other way? And if so, doesn't it unstabilize the magnetic. And why does the earth not get unstable when its magnetic lines of force break.

What is the physical difference between the two and how are they used to study electromagnetic waves in parallel and perpendicular AC electric fields.

How we can explain the inverse relation-ship between plasma density and Debye length physically ?

We consider small perturbation in plasma to understand the concept of plasma oscillation.

We take perturbation in velocity, density and electric field.

que-1 how do we create this perturbation (with what frequency, voltage and how ?). want to understand with physical example.

que-2 we consider small perturbation, how can we quantify this ?

que -3 what will happen if we remove the given perturbation ?

Thank you in advance,

With kind regards,

Purvi

I've known that one of the unresolved problems is the Coronal heating problem and there are already many theories to explain the illogical temperature at the Corona. I need to know what are the other problems in the field of Solar Physics and what are the challenges to explain these problems?

In some conditions we take average K.E. if electron in plasma as 1/2 KT and sometimes we take just 'KT'.

When should we consider what and why ?

Thank you in advance,

Purvi Dave

Why does the emission wavelength directly proportional to its duration?

In the following technical report, Klobuchar states, " The-earliest TEC results, obtained in the late 1950s, showed the first temporal and seasonal, behavior of the topside of the ionosphere."

Klobuchar, J. A.; Aarons, J.; Mendillo, M.; Allen, R. S.; a John P. Mullen; Seeman, D. R. & Basu, S. Total Electron Content Studies of the Ionosphere IONOSPHERIC PHYSICS LABORATORY - AIR FORCE CAMBRIDGE RESEARCH LABORATORIES - L. G. HANSCOM FIELD, BEDFORD, MASSACHUSETTS, 1973

available from: http://www.dtic.mil/dtic/tr/fulltext/u2/762481.pdf

A reference was not provided and I have not been able to find a paper from the 50s that discusses the first TEC measurements. Is anyone familiar with the research being referred to?

Cheers,

Alex

The charged particled trapped in the Van-Allen belts around Earth, maybe they affected by the natural Earth's rotational or wobbling motions and their distribution get disturbed and may reflect some radio disturbances or affect the TEC distribution in the ionosphere.

Lets take a 1 dimensional kappa distribution , there is any way to derive two dimensional and three dimensional kappa distribution from the given 0ne dimensional kappa distribution function. I would like to know to know whether there exists a general way which is applicable for any distribution functions

I just read an interesting paper by Smith et al. (2012, ApJ), where they describe four characteristic regions in the power spectra of turbulent magnetic field fluctuations:

1. f < 0.5 Hz: Ion Inertial Range, Spectral Index (SI) ~ 5/3

2. f \in [0.2,3] Hz: Ion Dissipation Range, SI ~ 3, generally steeper than 1 & 3

3. f \in [3,30] Hz: Electron Inertial Range, SI ~ 2.5

4. f > 30 Hz: Electron Dissipation Range, steeper than 3

My question is: What exacly controls the extent of the ion dissipation range and how can it be distinguished from the electron inertial scale?

Looking at a lot of observations of turbulence in the solar wind, one finds that the ion inertial range seems to directly turn into the electron inertial range, without showing characteristics of a steeper ion dissipation range. E.g. in the papers by Alexandrova et al. (2009, Phys.Rev.Let.), Sahraoui et al. (2009, Phys.Rev.Let.) and Bourouaine et al. (2012, ApJ) the ion dissipation range is either very small or even non-existent.

Also there are a lot of turbulence models, that do not take the ion dissipation range into account but rather go directly from Alfven wave turbulence to kinetic Alfven wave (KAW), whistler or Hall-MHD turbulence, e.g. the weakened cascade model by Howes et al. (2011, Phys.Plas.) or the Hall-MHD model by Galtier (2006, J.Plas.Phys.).

To my knowledge there are only few papers that deal with the ion dissipation range in detail, such as Voitenko & Keyser (2011, NL Proc. in Geoph.), who call this range the weakly dispersive range and explain it with non-linear interactions of KAW that can produce very steep slopes up to SI~5.

So much for the background. Now I would like to know: What are your thoughts on this? Have you encountered problems regarding ion dissipation? Do you know how to identify ion dissipation and electron inertial ranges in your data? What do you think controls the ion dissipation range? Why is it sometimes there and sometimes not?

Would the passage of a big IDP (Interplanetary Dust Particle) passing at some distance not be an alternativeand perhaps more likely source of such soliton events?

Just like those propagating in the wake of supersonic object moving in the air?

In 1989 I suggested that electricaly charged IDP could produce characteristic electric potential variations observable by a dipole or monopole antenna that passes within the Debye sphere surrounding the interplanetary moving object.

The passage of such an object should also generate plasma waves (why not Alfvén waves as well) to be detectable by an ad hoc antennas system in space?

A first paper had been published in 1989 by a student of mine in PSS

LESCEUX, J.M., LEMAIRE, J. & MEYER-VERNET, N.,

ELECTRIC DIPOLE ANTENNAE USED AS MICROMETEOROID DETECTORS.

Planet. Space Sc., 37, 1291-1302, 1989.

A second one in 1996 was published JGR by a PhD student (Peter Meuris)

MEURIS, P., MEYER-VERNET, N. & LEMAIRE, J.,

THE DETECTION OF DUST GRAINS BY A WIRE DIPOLE ANTENNA : THE RADIO DUST ANALYSER.

Journ. Geophys. Res., 101, 24471-24477, 1996.

Did you post your paper on arXiv.org? This is another friendly and free media to archive and easily circulate scientific papers in parallel to traditional copyright versions or reprints.

I was pleased to see that you are now active analysing ULYSSES data.

Please send me a pdf copy of your paper.

Best Joseph

PS: Give my regards to Mark Reynolds. I haven't heard from him for so many years...

Please ignore to give numeric explanation.

What I mean by this question is:

*There is a flare/CME eruption from an active region site (e.g., 11476). I know how to determine the possible area/volume/energy of a suace (foot-points) of a flare ribbon using the RHESSI hard X-ray data.*If I use some sort of theoretical small equations and use the observational data of TEMPERATURE, EMISSION MEASURE of GOES/RHESSI/YOHKOH, it may give any possibility, but I am not sure if it can be reasonable. I am looking for any code or technique that will help me to determine the possible amount of energy erupted from the active region of the Sun.

As some of the research papers suggest that low FIP (below 10 KeV) elements get enhance by factor of 3-4 in Corona from Photosphere, while high FIP (above 10 KeV) elements don't show this characteristics.

Does this effect conclude anything about energy transfer from Photospere to Corona ?

And if possible the methodology of extracting such datasets.

Takayuki Umeda et al. [Computer Physics Communications, 2001] suggested that an absorbing boundary can be used to absorb the outgoing electromagnetic waves. How can we deal with the particles at such boundary? Could you make some comments on it?

Ground-based vertical plasma drift is inferred from the time rate of change of hmF2 or h'F (the virtual height of the F-layer)

In one paper I got that said after using the equilibrium condition the secular term will vanish. What is the form of this secular term?

What is coronal loop? Where from it originates? What is its contribution to coronal heating? How to model it and which model is appropriate for theoretical investigation?