# Help - IMF polarity from ACE

• space0
In summary, the conversation discusses a comparison of real-time ACE IMF polarity data with Wang-Sheeley-Arge model predictions, using data from different solar observatories. The solid black line represents the real-time ACE IMF values, with positive and negative polarities indicating the direction of the IMF from the Sun to Earth. The conversation ends with a request for confirmation on the source of ACE IMF polarity data.

#### space0

IMF Polarity Predictions:
Comparison of real-time ACE IMF polarity data (solid black line) with Wang-Sheeley-Arge model predictions (colored dots). The three sets of predictions (i.e., red, green, and blue dots) are based on data from, respectively, Wilcox (WSO), Mount Wilson (MWO) and SOLIS (NSO) solar observatories. The solid black line is the real-time (9-hour-averaged) ACE IMF values normalized to equal unit value. A positive (negative) polarity indicates that the IMF is directed radially outward (inward) from the Sun to the Earth. Each 9-hour interval of real-time ACE data corresponds to 9 individual (hourly averaged) values when there are no gaps in coverage. If two-thirds of the 9 values have positive (negative) sign, they are assigned a polarity of +1 (-1). If less than two-thirds are of a particular sign, that time interval is assigned a polarity of zero, implying mixed or indeterminate polarity. Source : http://www.swpc.noaa.gov/ws/predimf_3d.html [Broken]

Referring to above image, based on data from Bz, 8 out of 9 numbers are positive polarity, but ACE shows negative polarity, I would like to confirm whether ACE IMF polarity come from data of Bz or not.

Does anyone have any suggestions?

Thanks in advance for any suggestions :>

Last edited by a moderator:
Does anyone have any suggestions?

## 1. What is IMF polarity?

IMF polarity refers to the direction of the interplanetary magnetic field (IMF) as it interacts with the Earth's magnetic field. The IMF can either be pointed towards or away from the Earth, and this polarity can have significant effects on our planet's magnetosphere and ionosphere.

## 2. How is IMF polarity measured?

IMF polarity is measured by spacecraft, such as the Advanced Composition Explorer (ACE), which measure the direction and strength of the IMF near the Earth. This data is then used to determine the polarity and other characteristics of the IMF.

## 3. What is the role of IMF polarity in space weather?

IMF polarity plays a crucial role in space weather, as it can affect the strength and direction of the solar wind, which can impact the Earth's atmosphere and cause geomagnetic storms. It also plays a role in the formation of auroras.

## 4. How does IMF polarity affect Earth's magnetic field?

The polarity of the IMF can cause disturbances in the Earth's magnetic field, leading to changes in the strength and direction of the field. This can have various effects, including causing disruptions in communication and navigation systems and affecting satellites in orbit.

## 5. Can IMF polarity be predicted?

While scientists can forecast the general behavior of the IMF, such as the occurrence of geomagnetic storms, predicting the exact polarity of the IMF is still a challenge. However, ongoing research and advancements in technology may improve our ability to predict IMF polarity in the future.