The Physics
Factbook
An encyclopedia of scientific essays

Density of the Solar Wind

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Bibliographic Entry Result
(w/surrounding text)
Standardized
Result
Kivelson, Atmo. Introduction to Space Physics. New York: Cambridge University Press. 1995. "The Solar Wind has an average density of 7.1 atoms/cm3" 7.1 atoms/cm3
Solar Wind. Columbia Encyclopedia. 2005. "Near the earth it has a density ranging from 3 to 6 atoms per cc, a velocity of 450 mi (700 km) per sec, and a temperature of about 1,300°F (700°C); during periods of greater sunspot activity it shows corresponding increases in density, temperature, and velocity—reaching speeds of 2 million mph (3.2 million kph)." 3–6 atoms/cm3
Explanation of Real-Time Solar Wind Data Dials. June 10, 2005. Latest Solar Wind Values
Created: 2005 Jun 12 1943 UTC
Magnetic Field
(Based on GSM coordinates)
Plasma
Total Field, B: 16.6 nT Speed, V: 495 km s-1
Field in x-direction, Bx: 1.3 nT Temperature, T: 3.6e+04 K
Field in y-direction, By: 7.4 nT Density, n: 3.0 particles cm-3
Field in z-direction, Bz: -14.8 nT Pressure, P: 1.2 nPa
Latitude angle, beta: -63.1°  
Angle, theta: 153.1°  
3.0 atoms/cm3
Parker, Eugene N. Dynamics of the Interplanetary Gas and Magnetic Fields. Astrophysical Journal. Vol. 128 (November 1958): 664. "These velocities of 500 km/sec and more and the interplanetary densities of 500 ions/cm3 (1014 gm/sec mass loss from the sun) follow from the hydrodynamic equations for a 3 × 106 °K solar corona." 500 atoms/cm3
Characteristics of the Solar Wind. Windows to the Universe. University Corporation for Atmospheric Research (UCAR). September 3, 2001. "At the orbit of the Earth, the solar wind has an average density of about 6 ions/cm3. This is not very dense at all!" 6 atoms/cm3

The Sun is a huge, luminous ball of gas. It is composed of about 90% hydrogen and 10% helium with a small fraction of other elements, such as carbon, oxygen, and iron. The solar wind is located on the outer atmosphere of the Sun, known as the Corona (which is Latin for Crown).

It is the supersonic outflow into interplanetary space of plasma from the outer atmosphere of the Sun. Its is composed of positive ions and electrons, with the ions being almost entirely composed of protons, about 95% to be exact. The elements that make up the Solar Wind are Hydrogen (95%), Helium (4%) and a mixture of Carbon, Nitrogen, Oxygen, Neon, Magnesium, Silicon and Iron at < 1%.

The average density of the Solar Wind is 4.0 atoms per cubic centimeter. Which is pretty small if you think about it, especially since the Solar Wind is responsible for deflecting the tails of comets away from the Earth.

The Solar Wind is constantly being blown off from the Sun at speeds of about 400-500 km per second. If you were to travel at 450 km per second you could travel around the entire world in 85 seconds! That's crazy!

Little is known about the affect of the Solar Wind on the Earth. Solar storms that do develop on the outer atmosphere of the Sun occasionally come in contact with the Earth which may damage electrical equipment.

Randy Abbas -- 2005