What is Fields: Definition and 1000 Discussions

FIELDS is a science instrument on the Parker Solar Probe (PSP), designed to measure magnetic fields in the solar corona during its mission to study the Sun. It is one of four major investigations on board PSP, along with WISPR, ISOIS, and SWEAP. It features three magnetometers. FIELDS is planned to help answer an enduring questions about the Sun, such as why the solar corona is so hot compared to the surface of the Sun and why the solar wind is so fast (a million miles per hour).The host spacecraft, Parker Solar Probe, was launched by a Delta IV Heavy on August 12, 2018 from Florida, USA. On August 13, 2018 FIELDS became the first instrument to be activated including beginning deployment of the 4 whip antenna (clamps unlocked) and extension of the magnetometer boom. On September 4, 2018 the whip antennas were deployed.

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  1. SherlockHolmes

    A Classical fields: EM fields vs. Gravitational fields

    I'm reading on Wikipedia about quantum field theory and read this: "Quantum field theory naturally began with the study of electromagnetic interactions, as the electromagnetic field was the only known classical field as of the 1920s". Why wasn't Newtonian gravitation regarded as a classical...
  2. Boltzman Oscillation

    Engineering How do I find the electric fields for this capacitor?

    the image is given here along with some numerical information: Now I know that the formula for the electric field in a capacitor is given as: $$E = \frac{V}{d}$$ which I can use to obtain the three following fomulas: $$E_1 = \frac{V_1}{d}$$ $$E_2 = \frac{V_2}{d}$$ $$E_3 = \frac{V_3}{d}$$ where...
  3. W

    I Differentiable manifolds over fields other than R, C

    [Moderator's note: Spin-off from another thread.] You need the structure of a topological vector field K with 0 as a limit point of K-{0}. The TVF structure allows the addition and quotient expression to make sense; you need 0 as a limit point to define the limit as h-->0 and the topology to...
  4. jisbon

    How are the angles involved in deriving magnetic fields for a current loop?

    So I have managed to derive the magnetic field of a current carrying wire, however, I seem to have some enquiries on deriving the one for the loop. In the formula where ##\frac {ds * r} {r^2}##, I know that it will become ##ds sin \theta.## However compared to the theta in the wire, the theta...
  5. Amartansh

    I Visualization of fields in waveguides

    Can someone provide me intuitive visualization of how E or H field can be longitudinal in a waveguide (TM/TE)? TEM is easy to visualize, but how EM wave can behave like sound in a waveguide (constant phase and amplitude plane in the same direction)? [Moderator: large bold font removed. In the...
  6. S

    Momentum from static E and H fields? (So this video claims)

    Is it true, what he's saying from 04:28 to 04:56 ? I have my doubts, but I thought I'd better ask here.
  7. C

    I Relationship between EM and matter fields in QED

    It seems that QED treats the matter and EM fields as independent yet coupled fields. On the other hand the EM field equations emerge immediately under local change of the phase of the matter field, exactly as required to reestablish local (gauge) invariance. From that perspective it almost seems...
  8. Bobjoesmith

    I Physical Meaning of a Quantum Field

    Sorry in advance if this question doesn't make sense. Anyway, I am reading a paper about quantum field theory and the Whitman Axioms (http://users.ox.ac.uk/~mert2060/GeomQuant/Wightman-Axioms.pdf), and it describes a field (Ψ) as Ψ:𝑀→𝑉⊗End(𝐷) where 𝑀 is a spacetime manifold, 𝑉 is a vector...
  9. L

    Engineering Magnetic Field Question (saturating an iron plate)

    I know that the field inside sample is a combination of the demagnetizing field and whatever applied field you may have. So these two fields together influence how big a field you need in order to magnetize the sample.
  10. R

    Other Using Databases like Scopus to Find Trends in Physics

    Hello everyone. My question is how can I use databases like scopus to know which areas of physics are the "hot" today or which are still in development.
  11. C

    Proving limits of electric fields on infinite planes

    rt a)
  12. bob012345

    Does matter exert a Force on Fields (or Light)?

    In a simple example of two current carrying wires, there are mutual forces. Do we speak of the forces on each wire as action-reaction or as someone I'm debating with, each wire and the fields from the other wire as action-reaction? Or both? Thanks.
  13. R

    Fluctuating Magnets: A Guide to Interacting Magnetic Fields

    How would it be possible to fluctuate one magnet between two magnets? Thanks
  14. A

    I Interacting fields in QFT and minimum excitations....

    Following up on @A. Neumaier's excellent series of articles on virtual particles, I'm confused about one thing (well of of several). If you pop over to the discussion of virtual particles on Matt Strassler's page, he mentions that, for example, an excitation in the photon (em) field will also...
  15. N

    I need some help with Magnetic Fields & Computer Science

    Lets say we have a Direct Current (not an alternating current) going through a wire ; so there is a steady-state magnetic field created around the wire. Then let's say we move some object into the magnetic field that disturbs the field. . My question is : How do we/they get information...
  16. S

    How to measure electric and magnetic fields in asymmetric capacitors?

    Summary: I need to build an asymmetric capacitor, but the mathematics of electromagnetics become too tough, do you have any info that can help? Appreciate it! Hello, I am an undergraduate student in engineering and I want to build an asymmetric capacitor, so I need electromagnetics which I...
  17. T

    Conditions needed for magnetic force on a conductor

    none
  18. P

    Relationship between paramagnetic fields and distance

    Summary: What is the relationship between paramagnetic field strength at a given distance from the source? Apologies if I have put this in the wrong topic. And apologies if the question is unclear, I am a biologist by background attempting to do some physics here! Basically I am looking to...
  19. Sophrosyne

    Electromagnetic waves in charged/magnetic fields

    Electromagnetic waves are oscillations of the electrical/magnetic field which propogate through space. So one might predict that the presence of a magnet/charged particle would effect their propogation somehow, like distortion or interference (eg, light might get refracted in a magnetic field or...
  20. U

    I Boundary conditions and discontinuity of EM fields

    Premise: everything that follows is done in the frequency domain. Boundary conditions If there are superficial currents (electric and magnetic) impressed on the boundary between two media, we have these discontinuities for the tangential components of the fields...
  21. Wrichik Basu

    B How do you find the Lagrangians for different fields?

    I am currently studying QFT from this book. I have progressed to the chapter of QED. In the course, the authors have been writing the Lagrangian for different fields as and when necessary. For example, the Lagrangian for the complex scalar field is $$\mathcal{L} \ = \ (\partial ^\mu...
  22. Wrichik Basu

    B Clarification of Notation - Fourier decomposition of fields in QFT

    I am studying QFT from A First Book of QFT. It is a very well-written book. However, due to some personal reasons, I cannot buy the printed book at this moment. So I borrowed this book from a person (who, in turn, borrowed it from his university library), and scanned it. Everything is fine...
  23. berkeman

    Windows 10 Question: Different check mark fields on icons on the desktop

    Sorry if this was already addressed in the other Windows 10 thread. What do the different check mark fields (round and square) mean in the icons on my new Windows 10 laptop's desktop? My Google search only turned up results on "green checkmarks" that related to Office 365 synching? Thanks <<...
  24. D

    I Electromagnetic Fields and the manipulation of Space-Time

    Summary: Mathematical and Physical queries in regards to Electromagnetic Fields and their manipulation of Space-Time. I recently started looking into Einstein's Field Equations, to get a better understanding of how mass distorts and curves the plane of Space-Time, however from doing this I...
  25. A

    I Coherence length of velocity fields

    I have came across a term "coherence length of velocity field ##\lambda## ",tried to search in the internet but doesn't find any result...will anyone please give a brief summary of this in this context..
  26. H

    Strange question about cancelling electric fields

    I am curious about the case where two electric or magnetic fields cancel each other out (I'm assuming this is possible). If a charged particle travels through the region where the cancellation exists, I am assuming the particle behaves as if no field exists. Does that area still have electric...
  27. H

    Do electric fields have their own separate inherent charge?

    I am assuming the answer is NO. I realize that the electric field of any charged object has an energy density, but I was curious to know it that same field has it's own 'charge density' so to speak, and that it would have a small secondary electric field of it's own. This would imply that...
  28. H

    Energy Density of Electric Fields: Is it the Sum of All Electrons?

    I understand that the energy of an electric field arises from the work put into gathering the electrons together to create the field. Bringing electrons close together requires energy because they naturally want to repel. This potential energy is stored in the field itself and the field has an...
  29. K

    Cell Metabolism and Static, Unidirectional Magnetic Fields

    Can anyone explain why an artificial magnetic field may or may not promote an increase in cellular metabolism?
  30. M

    I Larger assignment on Vector Fields

    Dear everyone. I'm doing an assignment on vectorfields and for most of the assignment I have to deal with tensors and tensornotation. The first assignment asks me to express the following vector and matrixproducts in tensornotation. $$\overline c = \overline a + \overline b \\ d=(\overline a +...
  31. Luke Tan

    I Transforming Vector Fields between Cylindrical Coordinates

    In dealing with rotating objects, I have found the need to be able to transform a vector field from cylindrical coordinate systems with one set of coordinate axes to another set. For eg i'd like to transform a vector field from being measured in a set of cylindrical coordinates with origin at...
  32. JD_PM

    Python How to plot vector fields in Matplotlib

    Hi, I want to plot the vector field ##\vec F = ye^x \hat i + (x^2 + e^x) \hat j + z^2e^z \hat k## The code I have tried: # The components of the vector field F_x = y*e**x F_y = x**2 + e**x F_z = z**2*e**z# The grid xf = np.linspace(-0.15, 2.25, 8) yf = np.linspace(-0.15, 2.25, 8) zf =...
  33. W

    I Are EM fields clouds of photons?

    Personally, I have trouble visualizing a flock of birds without the birds. I have the same trouble trying to visualize an EM field without the photons. More than once, I have been hounded off of the ham radio forums for mentioning the word "photon". As one ham radio operator put it, "We don't...
  34. S

    I Deriving E&B Fields from Plane Wave 4-Potential

    I'm trying to derive the electric and magnetic fields of a plane wave from the four-potential ##\mathbf{A} = (A^t , \mathbf{a}) ## in the Lorenz gauge. Given: ##\mathbf{A}(\mathbf{R}) = \Re \left( \mathbf{C} e^{i \mathbf{K} \cdot \mathbf{R}} \right)## for constant future-pointing lightlike...
  35. gibberingmouther

    Magnetic Fields from Current Carrying Wires

    I've had a lot of problems that involve a segment of current carrying wire, for example when you have a square loop of wire. I have a formula for "long" wires that is B = μ0 * I/(2 * π * d). Can I use this for shorter wire segments, and if not, what formula can I use?
  36. A

    Acceleration of an electron due to Magnetic and Electric fields

    I figured that we would simply add up the forces acting on the electron (the electric force Fe and the magnetic force Fb) and then equate this to the given acceleration multiplied by the mass of the electron like so. vector Fe + vector Fb = (mass of electron) (vector acceleration) since vector...
  37. SolitaryMan

    Studying Fields related to Quantum Information

    I am a master student in theoretical physics from Italy and I would like to know more about fields related to "Quantum Information". I've been to some seminars and I think that these fields are very interesting, but I need to understand before applying for a PhD. What should I do?
  38. H

    I Divergent vacuum uncertainty of fields in QFT, how to resolve?

    If you calculate the uncertainty of a scalar field in the vacuum state, i.e. ##\langle0\left| \phi^2\right|0\rangle##, you get a divergent integral that comes out to something like $$\frac{1}{4\pi^2}\int_0^\Lambda \frac{k^2 dk}{\sqrt{{m^2}+{k^2}}}$$ Where ##\Lambda## is some momentum cutoff...
  39. M

    Origins of magnetic fields from permanent static magnets versus current

    The videos from Veritasium explaining permanent static magnets and electromagnets were quite good I thought… But they have me a little confused with regard to the origins of magnetic fields generated by an electric current as opposed to a permanent static magnet from say iron. 1. An...
  40. E

    Electromagnetic fields are polarised when leaving a dipole antenna....

    at a point they become plain waves, how much will they be attenuated when 'received' by a spiral log periodic antenna Vs another dipole? Would an H field created by a loop antenna have less attenuation?
  41. Peter Morgan

    A The relationship between random fields and quantum fields

    My paper "Classical states, quantum field measurement", arXiv:1709.06711, has been accepted by Physica Scripta, https://doi.org/10.1088/1402-4896/ab0c53. The version as submitted to Physica Scripta on November 4th, 2018 is available as arXiv:1709.06711v5. I believe that anyone who puts some...
  42. J

    Can Electric & Magnetic Fields Coexist?

    For light it is said it has no volume and also it it waves of electric and magnetic field. But for electric and magnetic field you need space? So can they both be at the same time?
  43. L

    Can Rotating Magnets Create a Stronger Magnetic Field?

    hello, i have a doubt i bought some small neodimium magnets 8x3mm and now i would like to try some experiments with them i have a doubt: if i rotate one of these magnet around one of its parallel axis, very fast , near 1000000 rpm, what happens to the magnetic field produced by the magnet? if...
  44. Geofleur

    A Is the visualization of quantum fields as harmonic oscillators accurate?

    After learning that QFT describes particles as excitations of underlying fields, I've been trying to gain a more definite understanding of what it means; I came across this paper: https://iopscience.iop.org/article/10.1088/1361-6404/aaa032 Does the author say anything that is misleading? If...
  45. fresh_42

    B Mathematics in STEM fields: GATEKEEPER OR GATEWAY?

    I found this interesting article https://blogs.ams.org/matheducation/2019/02/14/mathematics-gatekeeper-or-gateway written by Mark Saul So the question is: What is mathematics: A necessary evil or the universal language physics is written with? If you tune in on a random tv quiz show and wait...
  46. C

    Service drop wire running to my house and EM fields?

    Hi, I have a case of elevated AC Magnetic field in the house, strongest nearest the electric meter and along the service drop line connecting the house to the street power lines. Should that service drop line measure no current or fields when I shut off my main circuit breaker? it seems shutting...
  47. K

    I Allowed fields in General Relativity

    How do you know what fields can be coupled with the gravitational field? Is there a general procedure for knowing it or we have to try out and see whether it makes sense or not?
  48. M

    Electric Fields from Linear Charges

    Homework Statement Am amount of charge Q is uniformly spread over a semi-circle of radius R whose center is located a distance A from the origin. What point charge would have to be placed at the origin so that the E field at the center of the circle is 0? (The open end of the semi-circle is...
  49. J

    What device can produce magnetic fields Iooking to buy

    I’m looking for a device to produce electromagnetic fields and how can u control the frequency emitted looking to build or purchase looking to experiment any information either reply publicly or inbox me
  50. PainterGuy

    B Do the fields extend to infinity in a solenoid and for a wire?

    Hi, I wanted to clarify a point about the magnetic fields of a solenoid and wire. Do the fields extend to infinity? In my opinion, they don't but they can assuming the current also goes to infinity. They don't extend to infinity for a limited amount of current because they need to follow a...
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