วันเสาร์, 20 เมษายน 2024, 4:55AM
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อภิธานศัพท์: อภิธานศัพท์ฟิสิกส์ (อวกาศ)
M
MeV Mega (million) electronvolt. A unit of energy used to describe the
total energy carried by a particle or photon.
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MICROWAVE BURST A radiowave signal associated with optical and/or X-ray
FLAREs.
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MIDDLE LATITUDES With specific reference to zones of geomagnetic activity,
"middle latitudes" refers to 20 deg. to 50 deg. geomagnetic.
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MOUNT WILSON MAGNETIC CLASSIFICATIONS
Alpha. Denotes a unipolar SUNSPOT group.
Beta. A sunspot group having both positive and negative mag-
netic polarities, with a simple and distinct division between
the polarities.
Beta-Gamma. A sunspot group that is bipolar but in which no
continuous line can be drawn separating spots of opposite
polarities.
Delta. A complex magnetic configuration of a solar sunspot
group consisting of opposite polarity UMBRAe within the same
PENUMBRA.
Gamma. A complex ACTIVE REGION in which the positive and nega-
tive polarities are so irregularly distributed as to prevent
classification as a bipolar group.
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N
NANOTESLA (nT) A unit of magnetism 10.0E-09 tesla, equivalent to a gamma
(10.0E-05 gauss).
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NEUTRAL LINE The line that separates longitudinal magnetic fields of oppo-
site polarity.
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P
PENUMBRA The SUNSPOT area that may surround the darker UMBRA or umbrae. It
consists of linear bright and dark elements radial from the sunspot
umbra.
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PERSISTENCE Continuation of existing conditions. When a physical parameter
varies slowly, the best prediction is often persistence.
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PHOTOSPHERE The lowest layer of the solar atmosphere; corresponds to the
solar surface viewed in WHITE LIGHT. SUNSPOTs and FACULAe are
observed in the photosphere.
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PLAGE An extended emission feature of an ACTIVE REGION that exists from
the emergence of the first magnetic flux until the widely scattered
remnant magnetic fields merge with the background.
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PLAGE CORRIDOR A space in chromospheric (see CHROMOSPHERE) PLAGE lacking
plage intensity, coinciding with polarity inversion line.
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PLAGENIL Spotless disc free of calcium plage
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PLASMA Any ionized gas, that is, any gas containing ions and electrons.
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POLAR CAP ABSORPTION (PCA) An anomalous condition of the polar IONOSPHERE
whereby HF and VHF (3 - 300 MHz) radiowaves are absorbed, and LF
and VLF (3 - 300 kHz) radiowaves are reflected at lower altitudes
than normal. In practice, the absorption is inferred from the
proton flux at energies greater than 10 MeV, so that PCAs and
PROTON EVENTs are simultaneous. Transpolar radio paths may still
be disturbed for days, up to weeks, following the end of a proton
event.
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POST-FLARE LOOPS A LOOP PROMINENCE SYSTEM often seen after a major
TWO-RIBBON FLARE, which bridges the ribbons.
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