Meteorologia spaziale

Velocità del vento solare Vento solare dei campi magnetici Apice radioflusso a 10.7 cm
Bt Bz

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CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: May 16, 2019 17.42 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2942
Begin Time: 2019 May 15 1710 UTC
Yesterday Maximum 2MeV Flux: 1254 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Issued: May 15, 2019 17.26 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2019 May 15 1710 UTC
Station: GOES15


Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

WATCH
Geomagnetic Storm Category G2 Predicted
Issued: May 14, 2019 18.38 UTC
Geomagnetic Storm Category G2 Predicted

Highest Storm Level Predicted by Day:
May 15: G1 (Minor) May 16: G2 (Moderate) May 17: G1 (Minor)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Emesso: May 14, 2019 14.48 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3629
Valid From: 2019 May 14 0132 UTC
Now Valid Until: 2019 May 14 2359 UTC
Warning Condition: persistence

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

ALERT
Geomagnetic K-index of 7
Emesso: May 14, 2019 9.01 UTC
Geomagnetic K-index of 7
Threshold Reached: 2019 May 14 0859 UTC
Synoptic Period: 0600-0900 UTC

Active Warning: Yes
NOAA Scale: G3 - Strong

Potential Impacts: Area of impact primarily poleward of 50 degrees Geomagnetic Latitude.
Induced Currents - Power system voltage irregularities possible, false alarms may be triggered on some protection devices.
Spacecraft - Systems may experience surface charging; increased drag on low Earth-orbit satellites and orientation problems may occur.
Navigation - Intermittent satellite navigation (GPS) problems, including loss-of-lock and increased range error may occur.
Radio - HF (high frequency) radio may be intermittent.
Aurora - Aurora may be seen as low as Pennsylvania to Iowa to Oregon.

WARNING
Geomagnetic K-index of 7 or greater expected
Emesso: May 14, 2019 8.40 UTC
Geomagnetic K-index of 7 or greater expected
Valid From: 2019 May 14 0839 UTC
Valid To: 2019 May 14 1200 UTC
Warning Condition: Onset
NOAA Scale: G3 or greater - Strong to Extreme

Potential Impacts: Area of impact primarily poleward of 50 degrees Geomagnetic Latitude.
Induced Currents - Power system voltage irregularities possible, false alarms may be triggered on some protection devices.
Spacecraft - Systems may experience surface charging; increased drag on low Earth-orbit satellites and orientation problems may occur.
Navigation - Intermittent satellite navigation (GPS) problems, including loss-of-lock and increased range error may occur.
Radio - HF (high frequency) radio may be intermittent.
Aurora - Aurora may be seen as low as Pennsylvania to Iowa to Oregon.

ALERT
Geomagnetic K-index of 6
Emesso: May 14, 2019 7.36 UTC
Geomagnetic K-index of 6
Threshold Reached: 2019 May 14 0736 UTC
Synoptic Period: 0600-0900 UTC

Active Warning: Yes
NOAA Scale: G2 - Moderate

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

ALERT
Geomagnetic K-index of 5
Emesso: May 14, 2019 7.24 UTC
Geomagnetic K-index of 5
Threshold Reached: 2019 May 14 0724 UTC
Synoptic Period: 0600-0900 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

ALERT
Geomagnetic K-index of 6
Emesso: May 14, 2019 5.45 UTC
Geomagnetic K-index of 6
Threshold Reached: 2019 May 14 0545 UTC
Synoptic Period: 0300-0600 UTC

Active Warning: Yes
NOAA Scale: G2 - Moderate

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

WARNING
Geomagnetic K-Index of 6 expected
Emesso: May 14, 2019 5.20 UTC
Geomagnetic K-Index of 6 expected
Valid From: 2019 May 14 0521 UTC
Valid To: 2019 May 14 1200 UTC
Warning Condition: Onset
NOAA Scale: G2 - Moderate

Potential Impacts: Area of impact primarily poleward of 55 degrees Geomagnetic Latitude.
Induced Currents - Power grid fluctuations can occur. High-latitude power systems may experience voltage alarms.
Spacecraft - Satellite orientation irregularities may occur; increased drag on low Earth-orbit satellites is possible.
Radio - HF (high frequency) radio propagation can fade at higher latitudes.
Aurora - Aurora may be seen as low as New York to Wisconsin to Washington state.

ALERT
Geomagnetic K-index of 5
Emesso: May 14, 2019 5.12 UTC
Geomagnetic K-index of 5
Threshold Reached: 2019 May 14 0512 UTC
Synoptic Period: 0300-0600 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Emesso: May 14, 2019 5.01 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3628
Valid From: 2019 May 14 0132 UTC
Now Valid Until: 2019 May 14 1500 UTC
Warning Condition: persistence

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

WARNING
Geomagnetic K-index of 5 expected
Emesso: May 14, 2019 5.01 UTC
Geomagnetic K-index of 5 expected
Valid From: 2019 May 14 0500 UTC
Valid To: 2019 May 14 1200 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

ALERT
Geomagnetic K-index of 4
Emesso: May 14, 2019 4.59 UTC
Geomagnetic K-index of 4
Threshold Reached: 2019 May 14 0500 UTC
Synoptic Period: 0300-0600 UTC

Active Warning: Yes

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

WARNING
Geomagnetic K-index of 4 expected
Emesso: May 14, 2019 1.32 UTC
Geomagnetic K-index of 4 expected
Valid From: 2019 May 14 0132 UTC
Valid To: 2019 May 15 0600 UTC
Warning Condition: Onset

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

WATCH
Geomagnetic Storm Category G1 Predicted
Emesso: May 13, 2019 20.04 UTC
Geomagnetic Storm Category G1 Predicted

Highest Storm Level Predicted by Day:
May 14: None (Below G1) May 15: G1 (Minor) May 16: G1 (Minor)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Emesso: May 13, 2019 8.59 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2940
Begin Time: 2019 May 11 1625 UTC
Yesterday Maximum 2MeV Flux: 13216 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

WATCH
Geomagnetic Storm Category G1 Predicted
Emesso: May 12, 2019 14.12 UTC
Geomagnetic Storm Category G1 Predicted

Highest Storm Level Predicted by Day:
May 13: None (Below G1) May 14: None (Below G1) May 15: G1 (Minor)

THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Emesso: May 12, 2019 9.00 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2939
Begin Time: 2019 May 11 1625 UTC
Yesterday Maximum 2MeV Flux: 7583 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Emesso: May 11, 2019 20.55 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3626
Valid From: 2019 May 11 0152 UTC
Now Valid Until: 2019 May 12 0600 UTC
Warning Condition: Persistence

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Emesso: May 11, 2019 16.42 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2019 May 11 1625 UTC
Station: GOES15


Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

WARNING
Geomagnetic K-index of 5 expected
Emesso: May 11, 2019 12.48 UTC
Geomagnetic K-index of 5 expected
Valid From: 2019 May 11 1250 UTC
Valid To: 2019 May 11 1800 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Emesso: May 11, 2019 12.44 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3625
Valid From: 2019 May 11 0152 UTC
Now Valid Until: 2019 May 11 2100 UTC
Warning Condition: Persistence

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Emesso: May 11, 2019 5.44 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3624
Valid From: 2019 May 11 0152 UTC
Now Valid Until: 2019 May 11 1500 UTC
Warning Condition: Persistence

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

ALERT
Geomagnetic K-index of 5
Emesso: May 11, 2019 2.23 UTC
Geomagnetic K-index of 5
Threshold Reached: 2019 May 11 0220 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes
NOAA Scale: G1 - Minor

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

WARNING
Geomagnetic K-index of 5 expected
Emesso: May 11, 2019 2.18 UTC
Geomagnetic K-index of 5 expected
Valid From: 2019 May 11 0218 UTC
Valid To: 2019 May 11 0600 UTC
Warning Condition: Onset
NOAA Scale: G1 - Minor

Potential Impacts: Area of impact primarily poleward of 60 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Spacecraft - Minor impact on satellite operations possible.
Aurora - Aurora may be visible at high latitudes, i.e., northern tier of the U.S. such as northern Michigan and Maine.

ALERT
Geomagnetic K-index of 4
Emesso: May 11, 2019 2.01 UTC
Geomagnetic K-index of 4
Threshold Reached: 2019 May 11 0200 UTC
Synoptic Period: 0000-0300 UTC

Active Warning: Yes

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

WARNING
Geomagnetic K-index of 4 expected
Emesso: May 11, 2019 1.52 UTC
Geomagnetic K-index of 4 expected
Valid From: 2019 May 11 0152 UTC
Valid To: 2019 May 11 0600 UTC
Warning Condition: Onset

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Emesso: May 7, 2019 18.54 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2019 May 07 1835 UTC
Station: GOES15


Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

ALERT
Type II Radio Emission
Emesso: May 6, 2019 5.43 UTC
Type II Radio Emission
Begin Time: 2019 May 06 0511 UTC
Estimated Velocity: 740 km/s

Description: Type II emissions occur in association with eruptions on the sun and typically indicate a coronal mass ejection is associated with a flare event.

ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Emesso: May 5, 2019 17.30 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2019 May 05 1715 UTC
Station: GOES15


Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

CONTINUED ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Emesso: May 3, 2019 13.10 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Continuation of Serial Number: 2935
Begin Time: 2019 May 02 1645 UTC
Yesterday Maximum 2MeV Flux: 2979 pfu

Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

ALERT
Electron 2MeV Integral Flux exceeded 1000pfu
Emesso: May 2, 2019 17.08 UTC
Electron 2MeV Integral Flux exceeded 1000pfu
Threshold Reached: 2019 May 02 1645 UTC
Station: GOES15


Potential Impacts: Satellite systems may experience significant charging resulting in increased risk to satellite systems.

EXTENDED WARNING
Geomagnetic K-index of 4 expected
Emesso: May 2, 2019 5.47 UTC
Geomagnetic K-index of 4 expected
Extension to Serial Number: 3622
Valid From: 2019 May 01 1907 UTC
Now Valid Until: 2019 May 02 1200 UTC
Warning Condition: Persistence

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

ALERT
Geomagnetic K-index of 4
Emesso: May 1, 2019 22.23 UTC
Geomagnetic K-index of 4
Threshold Reached: 2019 May 01 2222 UTC
Synoptic Period: 2100-2400 UTC

Active Warning: Yes

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

WARNING
Geomagnetic K-index of 4 expected
Emesso: May 1, 2019 19.07 UTC
Geomagnetic K-index of 4 expected
Valid From: 2019 May 01 1907 UTC
Valid To: 2019 May 02 0600 UTC
Warning Condition: Onset

Potential Impacts: Area of impact primarily poleward of 65 degrees Geomagnetic Latitude.
Induced Currents - Weak power grid fluctuations can occur.
Aurora - Aurora may be visible at high latitudes such as Canada and Alaska.

Tabella

Data Radio flux 10.7 cm SESC Numero di macchie solari Zona macchie solari 10E-6 Nuove regioni GOES15 X-ray Bkgd flux Brillamenti
X-ray Ottica
C M X S 1 2 3
Apr 27, 2019 67 0 0 0 A5.9 0 0 0 0 0 0 0
Apr 28, 2019 68 0 0 0 A6.0 0 0 0 0 0 0 0
Apr 29, 2019 67 0 0 0 A5.9 0 0 0 0 0 0 0
Apr 30, 2019 69 0 0 0 A5.7 0 0 0 0 0 0 0
May 1, 2019 68 0 0 0 A5.9 0 0 0 0 0 0 0
May 2, 2019 69 0 0 0 A6.5 0 0 0 0 0 0 0
May 3, 2019 70 11 260 1 A7.7 1 0 0 0 0 0 0
May 4, 2019 72 12 270 0 B1.2 1 0 0 1 0 0 0
May 5, 2019 74 14 280 0 B1.0 0 0 0 5 0 0 0
May 6, 2019 76 25 300 1 B1.4 7 0 0 10 1 0 0
May 7, 2019 79 27 410 0 B1.2 2 0 0 6 1 0 0
May 8, 2019 75 24 320 0 B1.0 0 0 0 0 0 0 0
May 9, 2019 76 25 280 0 A9.4 1 0 0 2 0 0 0
May 10, 2019 76 24 270 0 A9.3 0 0 0 0 0 0 0
May 11, 2019 78 26 260 0 B1.0 0 0 0 0 0 0 0
May 12, 2019 76 24 280 0 A9.9 0 0 0 0 0 0 0
May 13, 2019 75 23 160 0 A8.8 0 0 0 1 0 0 0
May 14, 2019 74 24 170 0 A8.7 0 0 0 0 0 0 0
May 15, 2019 74 13 150 0 A8.9 1 0 0 2 0 0 0
May 16, 2019 74 13 150 0 A8.3 0 0 0 0 0 0 0
May 17, 2019 72 13 150 0 A8.0 0 0 0 0 0 0 0
May 18, 2019 71 11 140 0 A7.9 0 0 0 0 0 0 0
May 19, 2019 68 0 0 0 A7.3 0 0 0 0 0 0 0
May 20, 2019 69 0 0 0 A6.7 0 0 0 0 0 0 0
May 21, 2019 68 0 0 0 A6.3 0 0 0 0 0 0 0
May 22, 2019 67 0 0 0 A6.3 0 0 0 0 0 0 0
May 23, 2019 67 0 0 0 A6.2 0 0 0 0 0 0 0
May 24, 2019 66 0 0 0 A6.3 0 0 0 0 0 0 0
May 25, 2019 67 0 0 0 A6.3 0 0 0 0 0 0 0
May 26, 2019 68 0 0 0 A6.3 0 0 0 0 0 0 0
Media/Totale 71 10 128 2 13 0 0 27 2 0 0

Grafico riassuntivo

Brillamenti

Solar wind

Solar Wind

The solar wind is a stream of plasma released from the upper atmosphere of the Sun. It consists of mostly electrons, protons and alpha particles with energies usually between 1.5 and 10 keV. The stream of particles varies in density, temperature, and speed over time and over solar longitude. These particles can escape the Sun's gravity because of their high energy, from the high temperature of the corona and magnetic, electrical and electromagnetic phenomena in it.

The solar wind is divided into two components, respectively termed the slow solar wind and the fast solar wind. The slow solar wind has a velocity of about 400 km/s, a temperature of 1.4–1.6×10e6 K and a composition that is a close match to the corona. By contrast, the fast solar wind has a typical velocity of 750 km/s, a temperature of 8×10e5 K and it nearly matches the composition of the Sun's photosphere. The slow solar wind is twice as dense and more variable in intensity than the fast solar wind. The slow wind also has a more complex structure, with turbulent regions and large-scale structures.

Solar radio flux at 10.7 cm

Solar radio flux at 10.7 cm

The solar radio flux at 10.7 cm (2800 MHz) is an excellent indicator of solar activity. Often called the F10.7 index, it is one of the longest running records of solar activity. The F10.7 radio emissions originates high in the chromosphere and low in the corona of the solar atmosphere. The F10.7 correlates well with the sunspot number as well as a number of UltraViolet (UV) and visible solar irradiance records. Reported in “solar flux units”, (s.f.u.), the F10.7 can vary from below 50 s.f.u., to above 300 s.f.u., over the course of a solar cycle.

Flares

Flares

A solar flare is a sudden flash of brightness observed over the Sun's surface or the solar limb, which is interpreted as a large energy release of up to 6 × 10e25 joules of energy. They are often, but not always, followed by a colossal coronal mass ejection. The flare ejects clouds of electrons, ions, and atoms through the corona of the sun into space. These clouds typically reach Earth a day or two after the event.

Solar flares affect all layers of the solar atmosphere (photosphere, chromosphere, and corona), when the plasma medium is heated to tens of millions of kelvin, while the electrons, protons, and heavier ions are accelerated to near the speed of light. They produce radiation across the electromagnetic spectrum at all wavelengths, from radio waves to gamma rays, although most of the energy is spread over frequencies outside the visual range and for this reason the majority of the flares are not visible to the naked eye and must be observed with special instruments. Flares occur in active regions around sunspots, where intense magnetic fields penetrate the photosphere to link the corona to the solar interior. Flares are powered by the sudden (timescales of minutes to tens of minutes) release of magnetic energy stored in the corona. The same energy releases may produce coronal mass ejections (CME), although the relation between CMEs and flares is still not well established.

The frequency of occurrence of solar flares varies, from several per day when the Sun is particularly "active" to less than one every week when the Sun is "quiet", following the 11-year cycle (the solar cycle). Large flares are less frequent than smaller ones.

Classification

Solar flares are classified as A, B, C, M or X according to the peak flux (in watts per square metre, W/m2) of 100 to 800 picometre X-rays near Earth, as measured on the GOES spacecraft.

Classification Peak Flux Range at 100-800 picometer
W/m2
A < 10e-7
B 10e-7 to 10e-6
C 10e-6 to 10e-5
M 10e-5 to 10e-4
X 10e-4 to 10e-3
Z > 10e-3

An earlier flare classification is based on Hα spectral observations. The scheme uses both the intensity and emitting surface. The classification in intensity is qualitative, referring to the flares as: (f)aint, (n)ormal or (b)rilliant. The emitting surface is measured in terms of millionths of the hemisphere and is described below. (The total hemisphere area AH = 6.2 × 1012 km2.)

Classification Corrected area
(millionths of hemisphere)
S < 100
1 100 - 250
2 250 - 600
3 600 - 1200
4 > 1200

Sunspot number

Sunspots

Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions. They correspond to concentrations of magnetic field that inhibit convection and result in reduced surface temperature compared to the surrounding photosphere. Sunspots usually appear in pairs, with pair members of opposite magnetic polarity. The number of sunspots varies according to the approximately 11-year solar cycle.

Sunspot populations quickly rise and more slowly fall on an irregular cycle of 11 years, although significant variations in the number of sunspots attending the 11-year period are known over longer spans of time. For example, from 1900 to the 1960s, the solar maxima trend of sunspot count has been upward; from the 1960s to the present, it has diminished somewhat. Over the last decades the Sun has had a markedly high average level of sunspot activity; it was last similarly active over 8,000 years ago.

The number of sunspots correlates with the intensity of solar radiation over the period since 1979, when satellite measurements of absolute radiative flux became available. Since sunspots are darker than the surrounding photosphere it might be expected that more sunspots would lead to less solar radiation and a decreased solar constant. However, the surrounding margins of sunspots are brighter than the average, and so are hotter; overall, more sunspots increase the Sun's solar constant or brightness. The variation caused by the sunspot cycle to solar output is relatively small, on the order of 0.1% of the solar constant (a peak-to-trough range of 1.3 W/m2 compared to 1366 W/m2 for the average solar constant).

Indici K



Oggi


0h
UTC
3h
UTC
6h
UTC
9h
UTC
12h
UTC
15h
UTC
18h
UTC
21h
UTC
3



Data


Estimated Planetary

Estimated Planetary

Data A Indici K (UTC)
0h 3h 6h 9h 12h 15h 18h 21h
Apr 28, 2019 5 1 1 2 1 1 1 2 2
Apr 29, 2019 5 2 2 0 1 1 2 1 1
Apr 30, 2019 5 2 1 0 1 2 1 2 1
May 1, 2019 11 1 2 2 2 2 2 3 4
May 2, 2019 12 4 4 3 2 2 2 2 2
May 3, 2019 7 2 2 2 1 2 1 2 3
May 4, 2019 10 1 2 3 3 3 2 2 2
May 5, 2019 4 2 1 0 0 1 1 0 1
May 6, 2019 5 1 1 0 2 2 1 2 2
May 7, 2019 5 2 2 1 1 1 1 2 1
May 8, 2019 3 0 1 0 0 1 0 0 1
May 9, 2019 7 1 2 3 2 1 1 2 2
May 10, 2019 7 2 2 1 1 1 2 3 3
May 11, 2019 25 5 4 4 4 4 2 3 4
May 12, 2019 4 2 1 1 0 0 0 1 2
May 13, 2019 6 1 1 1 2 1 2 1 2
May 14, 2019 36 3 6 7 4 2 3 4 2
May 15, 2019 6 1 2 2 1 2 2 2 1
May 16, 2019 8 2 2 2 1 2 1 3 3
May 17, 2019 5 3 2 1 1 2 1 0 1
May 18, 2019 5 1 1 2 2 1 0 1 0
May 19, 2019 3 0 0 1 1 1 1 0 2
May 20, 2019 6 3 2 1 1 1 1 1 1
May 21, 2019 4 1 2 1 1 2 0 0 1
May 22, 2019 4 0 1 2 1 1 1 1 1
May 23, 2019 5 1 1 1 2 1 1 1 2
May 24, 2019 5 1 2 1 1 1 1 2 2
May 25, 2019 4 1 1 0 1 1 1 2 2
May 26, 2019 5 1 1 1 0 1 1 1 3
May 27, 2019 6 3

Middle Latitude

Data A Indici K
Apr 28, 2019 4 1 1 1 1 1 1 2 1
Apr 29, 2019 6 2 2 0 1 3 2 1 1
Apr 30, 2019 4 1 1 0 1 3 1 1 1
May 1, 2019 8 0 2 2 1 3 1 3 3
May 2, 2019 13 4 3 3 2 3 2 3 1
May 3, 2019 8 2 2 2 1 3 1 2 3
May 4, 2019 9 1 2 3 3 3 2 2 1
May 5, 2019 4 2 1 0 1 2 1 1 1
May 6, 2019 5 1 0 0 2 3 2 2 1
May 7, 2019 5 1 2 1 1 2 2 2 1
May 8, 2019 2 0 1 0 0 2 1 1 1
May 9, 2019 8 1 2 3 2 2 2 2 2
May 10, 2019 7 1 2 1 1 1 2 3 3
May 11, 2019 19 4 4 4 4 3 2 2 3
May 12, 2019 5 2 1 2 1 1 1 1 2
May 13, 2019 5 0 0 1 2 2 2 1 3
May 14, 2019 23 3 5 5 4 3 3 3 1
May 15, 2019 8 1 2 2 1 3 2 3 1
May 16, 2019 9 2 2 2 1 3 2 2 3
May 17, 2019 7 3 2 2 1 3 1 1 1
May 18, 2019 8 1 1 2 4 2 2 2 1
May 19, 2019 3 0 0 1 1 2 1 1 2
May 20, 2019 7 3 2 2 1 2 1 2 2
May 21, 2019 4 1 2 1 1 2 1 1 1
May 22, 2019 5 0 1 2 2 2 2 1 1
May 23, 2019 5 1 1 1 2 2 2 1 2
May 24, 2019 6 1 2 1 2 2 2 2 2
May 25, 2019 3 1 0 1 1 1 1 2 1
May 26, 2019 6 1 1 1 1 2 2 2 3
May 27, 2019 2

High Latitude

Data A Indici K
Apr 28, 2019 6 1 1 3 2 1 2 1 1
Apr 29, 2019 3 1 1 0 1 2 2 0 0
Apr 30, 2019 5 1 1 0 1 3 2 1 1
May 1, 2019 10 1 2 2 3 3 2 2 3
May 2, 2019 19 3 4 4 4 4 2 3 1
May 3, 2019 9 2 2 3 3 2 1 2 2
May 4, 2019 22 1 3 4 5 5 4 1 1
May 5, 2019 2 1 1 0 0 1 1 0 0
May 6, 2019 5 1 1 0 3 2 2 1 1
May 7, 2019 4 2 2 1 0 2 1 1 1
May 8, 2019 1 1 1 0 0 0 0 0 1
May 9, 2019 7 2 2 3 3 1 0 1 1
May 10, 2019 5 2 1 2 2 0 2 2 1
May 11, 2019 63 5 4 6 7 7 5 3 2
May 12, 2019 4 2 1 2 2 0 0 1 1
May 13, 2019 9 1 1 1 3 2 4 2 2
May 14, 2019 45 3 7 6 5 4 4 3 2
May 15, 2019 4 0 2 1 0 1 2 2 1
May 16, 2019 5 1 2 1 2 1 1 2 2
May 17, 2019 5 3 2 1 1 2 1 0 0
May 18, 2019 10 1 1 4 5 0 0 0 0
May 19, 2019 1 0 0 1 0 0 0 0 1
May 20, 2019 3 2 2 2 1 0 1 0 0
May 21, 2019 2 1 0 0 0 2 0 0 1
May 22, 2019 2 0 1 1 2 1 0 0 1
May 23, 2019 4 2 1 0 3 1 1 0 1
May 24, 2019 3 1 2 1 0 1 1 1 1
May 25, 2019 1 0 0 0 0 1 0 1 1
May 26, 2019 1 1 0 0 0 0 0 0 1
May 27, 2019 3

About

The K-index quantifies disturbances in the horizontal component of earth's magnetic field with an integer in the range 0–9 with 1 being calm and 5 or more indicating a geomagnetic storm. It is derived from the maximum fluctuations of horizontal components observed on a magnetometer during a three-hour interval. The label K comes from the German word Kennziffer meaning “characteristic digit”. The K-index was introduced by Julius Bartels in 1938.

The Estimated 3-hour Planetary Kp-index is derived at the NOAA Space Weather Prediction Center using data from the following ground-based magnetometers:

  • Sitka, Alaska
  • Meanook, Canada
  • Ottawa, Canada
  • Fredericksburg, Virginia
  • Hartland, UK
  • Wingst, Germany
  • Niemegk, Germany
  • Canberra, Australia

These data are made available thanks to the cooperative efforts between SWPC and data providers around the world, which currently includes the U.S. Geological Survey, Natural Resources Canada (NRCAN), the British Geological Survey, the German Research Centre for Geosciences (GFZ), and Geoscience Australia. Important magnetometer observations are also contributed by the Institut de Physique du Globe de Paris and the Korean Space Weather Center K-index Watches are issued when the highest predicted NOAA estimated Kp-indices for a day are K = 5, 6, 7, or >= 8 and is reported in terms of the NOAA G scale. K-index Warnings are issued when NOAA estimated Kp-indices of 4, 5, 6, and 7 or greater are expected. K-index Alerts are issued when the NOAA estimated Kp-indices reach 4, 5, 6, 7, 8, or 9.


More info
Origine dati: NOAA, Wikipedia

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